You underestimate how complex facebook is nowadays. Even the core is much more than just people friending each other.
If you mean "mimicking on or two of the features" I'm with you :)
If you mean "mimicking on or two of the features" I'm with you :)
In its core, the app is just users who can friend each other.
Add AJAX to that... and tada, something that resembles facebook.
Scaling the app to be very reactive, available to millions accessing it at the same time, and with near 100% up time is where the hundreds millions of dollars go. (and all that data mining)