Financial bubbles are like bad relationships. You often can't tell for sure that you're in one until it's over.

But it's usually pretty easy to see the warning signs, of both bad relationships and bubbles, and brace yourself for the inevitable bout of weeping and binge-eating.

Which brings us to Facebook's IPO, and to The Huffington Post's latest Pulitzer-eligible feature, the Tech Bubble Death Watch.

As you have perhaps heard by now, the social network is about to dump a truckload of shares on the public, in an offering that will value it at more than $100 billion, a number most sentient humans agree is optimistic, to put it charitably. And yet people cannot get enough of this stock.

As you have also maybe heard, everybody and their grandmother thinks this is the sign of a new bubble in technology companies. And you know what? So do we. You can't always trust everybody and their grandmother, but sometimes they are absolutely right.

So this seems like the ideal time to launch what we're calling the Tech Bubble Death Watch. Here's how it works: Using a finely tuned analytical approach (guessing), we assign a numerical value between 1 and 5 to the day's big tech-bubble news. Higher numbers indicate a greater risk that we are in the insane-frenzy phase of the tech bubble. Lower number numbers mean your retirement money is safe for the time being.

So what number does Facebook's IPO deserve? A full-on five. It's just too big of a target for anything lower. This is a watershed moment for the bubble, the only one you can be sure that everybody and their grandmother is aware of.

Sure, sure, you can argue that this is more likely the beginning of the bubble than the end. The stock could well tank tomorrow in its first day of trading, a sign investors are being smarter than we think. Or it could pop for one day, then fall for a while and be propped up by bargain hunters -- again, somewhat rational behavior.

Update: The stock priced Thursday night at $38 a share, opened Friday morning at about $42 and was trading around $40 a share at lunchtime on Friday -- not a disaster, but not exactly a bubble-like runaway surge, either. At the same time, its latest market valuation of $118 billion would make it one of the 25 biggest companies in the S&P 500, if it were part of that stock index. Does that sound right to you? Here's the Huffington Post's live blog covering the first day of trading.

But if we are indeed in a new tech bubble, then this moment will be the one we all remember, like Netscape and Pets.com in Tech Bubble 1.0.

Also, how the heck can we launch a new feature like this with anything less than a five? It is decided. And it is arbitrary, we know, so save your hateful emails.

Let's go to the evidence.

First, here's what Facebook has going for it: It claims 900 million users, or 13 percent of all human beings alive. It does actually make money, unlike a great many Tech Bubble 1.0 companies. It will likely survive the eventual Techpocalypse, just as Amazon.com, Google and others did.

“What's happening now is nothing like the insanity that gripped the market in 1999,” CNBC shouty man Jim Cramer yelled recently, and he's probably right. Cramer's track record of accuracy is only slightly lower than the success rate of Sex Panther: Fifty percent of the time, Cramer is right every time!

But with all due respect to Jim Cramer, there are lots of red flags about this company, snapping crisply in plain sight.

Its revenue growth is slowing.

It hasn't quite figured out how this whole "cell phone" thing works yet.

Insiders will be dumping shares in an unusually big way at the IPO. Some 57 percent of the shares that will be available to the public will come from investors who bought the company early and are cashing in on the IPO, writes the Wall Street Journal -- a high percentage for any IPO, particularly for a tech IPO.

And yet these red flags are only serving to enrage the fury of investors wanting to buy more of the stock, which apparently also has about 900 million interested buyers. This lack of caution in the face of all evidence is maybe the biggest hallmark of a bubble.

The New Yorker's John Cassidy, author of the Tech Bubble 1.0 autopsy Dot.Con: The Greatest Story Ever Sold, is going with tech bubble. He suggests that, while the company may survive and thrive, just as several dot-coms survived the first bubble, investors must be on some high-grade hopium to give it a valuation of $100 billion (and possibly more, after tomorrow's trading): "In purchasing its stock, as with buying the original dot-com stocks, investors will be laying out their cash primarily on the basis of hope and optimism rather than a clearly defined and firmly established business plan. To me, at least, that has echoes of the past."

PC Magazine's John Dvorak also decides that the true measure of the bubbliness of the Facebook IPO will be its legacy -- how many copycats rush to market, chased by investors looking for the next hot thing. He believes a successful Facebook launch means "the floodgates of bored money will pour into every idea that can put together an offering of any sort. It is 1999 again."

But Dvorak also warns the bubble could keep swelling for years to come: "We often forget that the Netscape IPO, which helped trigger the dot-com bubble, was in 1995—the very beginning of a five-year ramp. If Facebook triggers a similar bubble, then it will burst in 2017."