Facebook's astronomic rise, staggeringly large user-base, and world's youngest self-made billionaire CEO make it one of the most fascinating companies around today.

While everyone knows the basics about the service's Harvard dorm room origins, we've delved a little deeper to find out more interesting snippets of info.

Here are 10 facts you might not know about Facebook, so read on and let us know your favorites in the comments box below.

1. Al Pacino's Face Was on the Original Facebook Homepage

Prior to a major homepage redesign back in 2007, Facebook's front page used to feature a man's face partly obscured behind a cloud of binary code.

Dubbed the "Facebook guy," it was not known who the mystery man was — until recently. David Kirkpatrick has revealed in his book The Facebook Effect that the image is a manipulated photo of Al Pacino created by a friend and classmate of Mark Zuckerberg.

2. One Early Facebook Function Was a File Sharing Service







You won't find this in the official Facebook timeline, but one of Facebook's early add-ons was a peer-to-peer, or more technically friend-to-friend, file sharing service called Wirehog, developed alongside Facebook by Mark Zuckerberg and three others.

It launched in 2004 and is reported to have been planned as an integral FB feature. In 2005 Facebook was actively promoting the service and Zuckerberg told The Harvard Crimson "I think Wirehog will probably spread in the same way that thefacebook did."

However, likely due to piracy concerns, Wirehog was axed in 2006 before Facebook got really big, although its photo-sharing functionality lives on in spirit.

3. The First "Work Networks" Included Apple and Microsoft







Many of you may know about Facebook's initial staggered rollout, where they started with Ivy League colleges before encompassing other educational institutions. But do you know who Facebook first went corporate with in terms of official work places?

In May 2006, Apple and Microsoft were among the first, as was Intel, EA and Amazon. Others in the first round also included Accenture, Gap, Intuit, Pepsi, PricewaterhouseCoopers and the non-profit organization Teach for America. It wasn't until September 2006 that everyone, regardless of school or company affiliation, could join Facebook — and just over a year later the site hit 50 million active users.

4. Facebook's Hidden Easter Eggs







Facebook is no stranger to Easter eggs. Early on, mysterious movie-related references (apparently Zuckerberg is a big film buff) could be found littering the site.

The references could be found in the footer of the old "Friends Page" in 2007, and one of the first was a quail-themed quote from the film The Wedding Crashers. Later dubbed "quails," other quotes with the avian theme continued to appear in the footer text, including “Only the craftiest of quails survive hunting season,” and “What doesn’t kill a quail only makes it stronger."

In addition, Facebook once boasted a Konami Code (you know — up, up, down, down, left, right, left, right, B, A, enter) that changed the background of the site to display colorful circles and light flares.

Finally, there's the "Chris Putnam," a Facebook Chat Easter egg that still works today. To test it out, when in chat type in :putnam: and hit enter — ta da!

5. The Meaning of the Term Poke Has Never Been Defined







While Facebook explains how "poking" works on its help center, there's no explanation to be found for the origin of the phrase. The most common definition is a friendly "nudge," but the more flirtatious connotations cannot be ignored.

David Kirkpatrick reveals in The Facebook Effect that Zuckerberg once responded to a question about what a poke meant on the social networking site with: "We thought it would be fun to make a feature that has no specific purpose... So mess around with it, because you're not getting an explanation from us."

6. The Average Facebook User Has 130 Friends







How many Facebook friends do you have? To put your friend count in perspective, the average user has 130. Facebook's official stats page is full of little gems like this, and more staggering stats, such as the fact that people spend over 500 billion minutes per month on Facebook, while the current active official user count now stands at over 500 million.

As far as Facebook the platform goes, over a million websites have integrated with Facebook, and more than 150 million people engage with Facebook on external websites every month.

7. There's an App to See What's on the Facebook Cafe Menu







Like at Google, Facebook staffers get three free meals a day (as well as free drinks and snackage) served up by the "Facebook Culinary Team" at Cafe X or Cafe 6.

If the staff want to know what's on the menu, they don't need to leave their seats. In fact, they don't even need to leave their Facebook profiles — the "Lunchtime" Facebook app offers a weekly view of what's being offered. And it looks real good.

8. Mark Zuckerberg Calls Himself a "Harvard Graduate"







As you can see for yourself over at facebook.com/zuck (the personalized URL Zuckerberg nabbed for himself), Mark Zuckerberg tells a little fib on his profile page. He lists himself as a "Harvard Graduate," which simply isn't true, as he dropped out to concentrate on getting Facebook up and running.

When 60 Minutes reporter Lesley Stahl confronted Zuckerberg with this little inconsistency, he said "That's true. We don't have a setting for dropout."

Er, memo to Zuck — you kind of have the power to make that happen...

9. California is Huge on Facebook







As far as Facebook goes, California (home of Silicon Valley) is the most social state, with an amazing 15,267,160 users in the region, according to Facebakers. This amounts to a 41% penetration rate — pretty astounding that nearly half the state is connected via Facebook.

The next biggest user-base can be found in Texas with 9 million users, but it's nowhere close to California. New York comes in third with 8 million, and rounding off the very bottom of the list is ... Delaware. Of course, actual state population size is a factor here, but you get the point.

10. A Facebook Employee Hoodie Sold for $4,000 on eBay







If Facebook merchandise is collectible now, imagine what it will be worth in years to come. A Facebook employee standard-issue hoodie recently sold on eBay for a whopping $4,050 with nearly 50 bidders battling it out to win the auction.

The fact that Mark Zuckerberg had just been seen sporting the same garment at the D8 Conference and revealed its mysterious insignia to the world certainly helped up the bids, but considering the one that sold had not touched Zuckerberg skin, it's an astonishing amount.

More Facebook resources from Mashable