Even as Facebook (NASDAQ:FB) has begun to rally after its most recent quarterly earnings, the social network is demonstrating that it can execute in growing its core ad business as it transitions to mobile platforms. Google (NASDAQ:GOOGL) still can't compete meaningfully as a social network with Google Plus, and Facebook is even taking some cues from Big G's experimental ways by testing new initiatives.

While investors initially had pinned their hopes on Facebook's platform business, the storyline has shifted to its mobile ad platform and user engagement remains high. Now, any growth in the payments business is just gravy on top.

In the following video, Fool contributor Evan Niu, CFA, and Eric Bleeker, CFA, discuss why they're optimistic about Facebook's future, despite recent gains.