The sourse of FaceBook is no other then mark zuckerberg! Read about him on Wikipedia. He has an amazing story. And I recommand to see the new movie about him "Social Network". It explains alot. :]
If you mean the source code you can right click a page and click view source code. That will show you Facebook's code for that page.
A library is a far more reliable source than Facebook
Facebook has more traffic according to the source listed in the related links section below.
Mark Zuckerberg created Facebook on February 4, 2004 Source: http://en.wikipedia.org/wiki/Mark_Zuckerberg#Facebook_in_2009
Just right click and then click View Page source.
Did you find this on View source? You cannot remove it.
Facebook uses open source software, including the Linux operating system, Apache web server, and MySQL database. Many other large online sites use open source software; for example, Google and Wikipedia use Linux servers.
Myspace
To get the code for any website, simply right click on it, then select view page source.
Michael Jackson got surpassed by Eminem at 40,872,548 fans compared to Jacksons at 36,034,929 this was written on the date of June 15th 2011(my source is Google and facebook)
Default layouts for Facebook can be found on a site called TotallyLayouts. There are many other sites as well. These include, but are not limited to, LayoutFever, Coolchaser, and Free Code Source.
Nope, he's Still Alive...And Well! Source: His Facebook, site