I'm always getting criticized for writing long blogs. "Way too verbose! Couldn't he have said all that in two paragraphs?" Not everyone feels that way, of course; lots of people tell me to keep doing what I'm doing. But the size critics are doggedly persistent. And I don't think it's just people who are slow readers. Even friends of mine will sometimes advise me to trim my entries down, which is a surprise, since I thought most of them would have picked up on the cause and effect relationship between blog length and popularity. Evidently not!So, like, let's get this out in the open: I'm doing it on purpose. Yes, sure, I could do with an editor (the people kind), but only if said editor were on board with long blogs, because that's the kind I want to write.In short, I think long blogs have better survival characteristics: greater reach and greater impact. And I've decided to celebrate the august occasion of the 1000th kneebiter publicly maligning my style by explaining why I do it. And yes, it'll be long. Set aside at least 20 minutes to read this thing. You've been warned!Let's start with the obvious. People expect blogs to be short – at least, shorter than mine. They expect that because it's pretty much how everyone does it. Short entries, and frequent. Here's my cat today. Doesn't he look sooo different from yesterday? No wonder so many people hate bloggers.When I write my long blogs, I'm bucking established social convention, so it's natural that some people will whine that they're too long.Well, how far off cultural expectations am I? Doing a quick print preview in my browser shows that my last entry, formatted at about 14 words per line (typical for a printed book) weighs in at about ten pages. So it's roughly essay-sized. I'm not talking about those toy five-paragraph essays they made you write in high school. I'm talking about real-life essays by real-life essayists . Real essays can range from three pages to 30 or more, but ten pages is not an unusual length.If I were attempting to publish these entries as books, publishers would laugh at me. They're way too short to be books. Sure, I could bundle them, but that's beside the point. The fact is, two different real-world audiences have entirely incompatible views on what the proper length for my writing should be.I like to shift between writing articles and essays. The two overlap to some extent, in that an "opinion article" can be essay-like. But an essay attempts to be richer and deeper than an article. Essays can take all sorts of forms – prose, poems, stage plays, screenplays, short stories, even songs. And yes, they can take the form of blog entries.Essays have different goals: some introduce new ideas, some aim to change minds that have been made up, some try to rally people to a cause, some just poke fun. Regardless of the goal, I think what unites them as essays is that they strive to imprint the reader with an idea, some hopefully unforgettable perspective, even if the reader doesn't necessarily agree with it.Essays might use humor to endear you, or satire to shock you, or storytelling to entertain and lull you, or logic to convince you, or rhetoric to persuade you, but in the end they're trying all trying to imprint you with a little piece of the essayist's personal perspective on life.So we've established that my longer entries are for the most part essays in blog form, with nary a cat picture to be found. I think the appearance of my entries in feed-readers alongside cat pictures and other non-essays is a big contributor to why so many people feel they're too long. If I instead herded them off into a page titled "Essays", as essayist Paul Graham does, then my guests might arrive with more appropriate expectations.But let's face it – that's more work. Blogs are the closest thing we've got today to a ready-made, turn-key, high-availability essay publishing system, one that permits comments, subscriptions, biographical links and the other trappings you'd expect. It's not ideal – I even talked about this in my first-ever Blogger entry, but none of the issues I raised then have been resolved, doubtless because most people don't write essays, so there isn't a pressing need.Blogging's the best medium I've got today, so that's where I publish my essays.Amusing true side-story: I met Paul Graham at Foo Camp last summer. After his crowd of admirers had dispersed on the first day (he's pretty famous), I came up and introduced myself. He was very nice and polite, and he was even kind enough to venture: "I've read some of your ...essays." He said the word essays with this funny pained look on his face, as if he'd just swallowed a gob of wasabi and was trying to play it off like nothing was wrong. I think he meant well, but that expression was just priceless.I already knew my work wasn't for everyone. :)Anyway, there's more to the long-blog problem than mere expectations. You can still make a valid argument that my entries are too long even for essays, or at any rate for the material I'm covering or the points I'm making. And I'll still disagree with you. Let's see why.So, I have this pet theory I'm going to foist on you. It's probably total hokum, and someday I may be proven as wrong as Lamarck , but for now it's a hypothesis that fits the data pretty well.First, let me tell you what the pet theory is about. I talked about it a little in an essay I wrote in 2004, You Should Write Blogs . In the essay I outlined some unexpected behavior of an essay my friend had written and circulated at Amazon: nobody read the thing, but somehow a year later everyone knew about it, and its core message had been imprinted on everyone in the company, up to and including the executive staff.In the intervening three years since I wrote that essay, my own blog has taken off to level that can only be described as absurd. I've been lampooned in web comics , discussed endlessly on Reddit Slashdotted , invited to Foo Camp and various big conferences , approached about writing books, recruited constantly, and heckled mercilessly by my coworkers, all of whom are smarter than I am, both technically and also in the sense that they don't make public asses of themselves once a month.It's undeniable that I'm doing something right, at least in terms of reach. My blogs may or may not be any good, but they're widely read. So are they really too long?Well, people always tell me: "Steve, you'd be doing yourself – and us – a huge favor if you just made your entries shorter." So I try it now and again, and I've observed a correlation between blog size and splash size. It's as if you're all in a pond, and I'm throwing a rock into it. Bigger rock, bigger splash.I think you can actually stretch that metaphor one more level. I think if I throw in a sufficiently large rock, it'll crush you, which for most of you is an undesirable outcome. The rock needs to be big enough to splash you and get you all wet, but it shouldn't kill you.To translate that bizarre thought into non-metaphorical terms, a blog that's too big will cause "too many" readers to drop off, for some value of "too many". A longer entry means that fewer people will read it immediately, although I'd argue based on experience that longer entries that are worth reading will ultimately achieve a wider audience. It just takes longer for them to make the rounds - sometimes months or years. But there's a tradeoff there. It can be useful to make a big splash all at once, in the style of Gladwell's Tipping Point.So we've got a tricky number to solve for. Very short entries get ignored; I've tried that. Longer entries can make a splash but may not have broad long-term staying power. Very long entries tire people out, so they can take years to make the rounds. What's the right length for making a big splash the day it's published?That's where my pet theory comes in. Oh, you may laugh! Ha, ha, you might say! But I, who know absolutely nothing whatsoever about Cognitive Science , have a pop cog-sci theory about the right length for an essay.The right length for an essay, I believe, is exactly "one sitting": no more, no less. You should be able to read and absorb it fully in one go, with no breaks. Moreover, after you finish, you should be at the point where you need to take a break. You should want to stand up, stretch your legs, grab a coffee, play some foosball, get your mind off everything for a while. If you don't need a break after the essay, then it wasn't long enough.I suspect the maximum length for a "sitting" is 50 minutes, given various government studies I learned about while I was in Navy Nuclear Power School. They determined that people absorb information best (and concentrate best) in school in 50-minute intervals with 10-minute breaks. They'd figured out all sorts of other stuff too: use outline form, make the students copy the outline into a notebook, repeat everything exactly 3 times, and so on, all ways they'd found that lead to better retention of the material. But the 50-minute thing seemed intuitively reasonable. Those ten-minute breaks were indispensable.I actually think 50 minutes is the absolute upper bound for a sitting; the optimal duration is probably lower. But the takeaway here is that one consequence of my pet theory, which we'll get to shortly, is that the ideal length for a blog is measured as a duration, not a word count.Of course, that presents a problem, because duration is a function of word count and reading speed. I need to account for different personal speeds, and some folks like to read slowly. Heck, some don't even read at all. It's one of the amazing miracles of the internet: write-only people. They can't read but they somehow find a way to write. You see them commenting all the time in my blogs: "I didn't actually read your entry, but allow me to comment on it all the same..." Lovely.So I need to aim for something lower than 50 minutes, to make it possible for average readers, and then hope that for fast readers I'll still have blown their entire page cache. Being a fast reader is actually a disadvantage here.Figured my pet theory out yet? I'll bet some of you have!My pet theory is predicated on the hopefully obvious axiom that our brain is a computer. As a computer, even though it's structually different from a von Neumann machine, it's still constrained by the same laws of physics. Hence, it probably has a multi-level cache.I have some even more farfetched pet theories about the architecture of this cache, but whatever the architecture, caches all share the property of being limited short-term storage.I really want to talk more about how I think this cache works, and I keep deleting paragraphs about it. I'm in a bind: if I talk more about it, my pond-boulder will get too big and crush people. But if I don't, then I'll be accused of grossly oversimplifying.So it goes. Let's oversimplify.Your brain clearly has at least two obvious caches: your short-term memory and your long-term memory . Your long-term memory is more complex than a cache, but behaves like a cache in the way it forgets things that aren't refreshed periodically.The Wikipedia entry on short-term memory, linked above, says short-term memory lasts about 20 seconds. And long-term memory, of course, is persistent and can last up to a lifetime.My pet theory posits the existence of at least one second-level cache in your brain that holds data for a while before deciding whether to commit it to long-term memory. That "while" varies but is at least 10 to 15 minutes.Of course, writing the theory down like this makes all the holes in it pretty obvious, and I'm way too lazy to try to patch them all up here. Following the best academic tradition, I leave the hole-patching as an exercise for the reader.In my pet theory of the brain, such as it is, your second-level cache keeps track of all your sensory input for the past few minutes. It also serves as a scratchpad area for doing computation: if you're trying to follow a complex argument, you need to construct a graph: idea A leads to B and C, C implies D, etc. Even following a scene in a story requires a graph and some computation: think of a bank robbery movie scene with five people involved. Following its progress requires a little short-term memorization and some deduction, and your mind does this for you automatically for situations up to a certain low level of complexity.What about bigger arguments and more complex scenarios? Well, if the graph is too big to fit in your second-level cache, then your brain needs to swap some ideas to "disk" (your long-term memory). This is also known as "learning stuff." Painful, I know. I've been there.So my pet theory is that if you want to make a lasting impression, then you need to fill up the reader's second-level cache and start blowing pages (cache elements) out into their long-term memory. If you want to imprint them with something memorable, you've gotta flush it to disk. To fill the cache you have to create a story big enough to fill their short- and medium-term memory and start spilling over into long-term memory, at which point you're guaranteed that some of it will stick. It won't be just another funny blurb that your reader sees, laughs at, and immediately forgets.This obviously entails some effort on the part of the reader, even if they're having fun. You watch a 2-hour movie and you'll be exhausted (or at least ready for a break) because your brain is busy swapping stuff out. It uses more energy because of those pesky laws of physics that led to the cache structure in the first place.I think this whole idea scales up to N-level caching; if you write a whole book about something, and the reader manages to get through it all, then you've probably left them with a lot more long-term memories and patterns.But a good essay is usually just trying to get one idea across. One idea, one big rock in the pond: one sitting, one story. That's my theory. And it's the thesis of this essay, with the conclusion being that the relationship between blog length and popularity is actually causative.In the spirit of filling your second-level cache, I'd like to offer you just one detail of my pet architecture: I think our caches are only partly LRU; I think there's some randomness involved in which pages your short-term memory chooses to discard when you're interrupted with new data. In fact, if anything, they may be MRU (Most Recently Used), given that when you're having a conversation with your friend and you both get interrupted, you often can't remember the thing you were just now talking about, but you can both remember things you talked about a few minutes before.If that's true, then the stuff that gets swapped to disk is probably different for every reader, and may be somewhat random. In other words, everyone comes away with some different memory of the essay. It's likely also in no small part a function of how well any given turn of phrase is a match for the reader's experience. So a good essay needs to try to say the same thing in a bunch of different ways, hoping that whenever the reader's brain decides to latch onto something that "strikes" them more or less permanently, it's hopefully related to the core message of the essay.So everyone gets something different. But I think that's a good thing. If the readers come away thinking about it at all, the essay has succeeded.There's more I could say about my style. Expectations and page-caching theories aside, I think there's entertainment value in a good story-essay; you can't really weave in good jokes without some supplemental material, for instance. And I like to tackle inherently complex topics because they're more interesting, so it's never as easy as summarizing with something as pithy as "Java sucks". It's not that simple, no matter how people want it to be so.So yes, there's more I could say, but my gut tells me I've reached the one-sitting limit. So I'll wrap up here.I know I've oversimplified. I know I have no business talking about cog sci when I've never even read a book on it, unless you count Gödel, Escher, Bach . And I know that even if I'm right, I may still sometimes overshoot the ideal length significantly.But I'm convinced, and I hope you are now as well, that my blog entries are successful because of their length, and not in spite of it. It's OK if you don't agree with my pet theory as to why the longer ones are more successful; I've certainly got nothing but intuition backing me up here. But by getting you to disagree with it, I've left my mark. At least you'll remember the idea now. Consider yourself imprinted. This one's on the house!At this point I recommend stretching your legs. Take a walk, get some fresh air, let those disk drives cool down. You can ponder this stuff later. It'll still be there in your brain, like it or not. I guarantee it.