Is it a necessity?
Is it something you would pay for?
Is it something you HAVE paid for?
At what point does it become moot? (As in, after a few thousand likes or so does the return on social proof diminish?)
I'm thinking of purchasing a social proof package for a new site, but I'm unsure of whether or not it will really be as beneficial after a certain amount of likes/followers on the corresponding Twitter and Facebook page.