I think that social applications like Facebook or Google Plus are a fantastic example of a case where "my friends all use it" is the primary draw, though. They

I think that social applications like Facebook or Google Plus are a fantastic example of a case where "my friends all use it" is the primary draw, though. They exist so that you and your friends can interact (and view ads, of course). So if your social circle refuses to use Social Platform X you have very few reasons to use it yourself. Regardless of how silly you may think the reason you friends have for avoiding it, the fact of their avoidance is enough to make it not particularly useful to you. Sure, you should still understand the reason that other people want to use these platforms. But, having understood that, there's no reason to use them if they aren't actually of use to you.