If you wanna make money online so you can develop an application on facebook. Once Application get popular so you can earn a lot from that application. Many companies are developing facebook applications and they are earning alot from it because when any application gets popular so they are earning from it.


Creating an application for social network is also a very good business

It all depends.
We developed a Facebook app for for my company and it basically turned out to be a waste of time. The number of users was only in the low 5 figures. Conversions were miniscule.

Successful facebook apps may do well but even then, I have doubts about how well they monetize.