[henrikberggren]

I get what you mean and it's probably a fair assumption. But, the data you showed and the conclusion you draw "Won't be adding that FB button soon" is totally illogical. You have no idea how many ppl. that are coming to grove, want's to sign in but don't because they have neither a twitter or github account and/or don't want to sign up with it.

You need to add a FB signup button, test the increase (or non increase) of signups and then draw conclusions. Or measure bounce rates in some smart way. Your current method isn't very scientific.