"let's put no ads on our site and we'll destroy facebook's network effects, surely that'll work!"
Although, yes, as Badoo gives users the ability to do what companies have done for years is new, but it's still advertising, something they claim they've abandoned.
Facebook is vulnerable. The obvious way to hijack is to pull a Facebook on Facebook itself -- ask for your FB password and then copy out all your information, and msg all your friends.
If you could click a button and do a horizontal transfer to an equivalent service any time some other service crossed the line of what's acceptable to you, people would migrate in droves. Big companies survive because of inertia -- the truly disruptive technology that the Net should enable is to remove it.
Facebook's evil ways will doom it.