The 2005 version is pretty trivial: each profile has friends, a scrapbook (known on FB as wall), and up to 12 pictures; Communities (forums) have topics and top

The 2005 version is pretty trivial: each profile has friends, a scrapbook (known on FB as wall), and up to 12 pictures; Communities (forums) have topics and topics have posts. That's it. Any junior dev can build it on Rails/Django. The tricky part is scaling it. The original version as a .NET app and it couldn't handle the number of simultaneous users.