Weirdness, the way I interpret it, is another way to say strong personality. If you're weird compared to your peers, you probably have a different view about things. And most likely a very very specific view about that very very concrete topic you care about.
This has everything to do with niche social media. I'm not going to talk about why Google+ never really took off (or maybe it did, no one really knows actually), but I do know why I never really started using it for real. And no, it's not about the crickets.
Google+ failed to tell me from the very beginning what the hell am I supposed to do there that I don't already do on Facebook. Is it about the circles? Meh. Ok, it's a nice concept. It's not something that will make me abandon the platform where I have my social graph for something where I have... basically none of those people as active users.
Take on the other hand niche social media, where I consider Pinterest and Instagram, for instance. I don't call these niche because of how many people are there (I already know they are a gazillion), but because of the specific actions they tell us to do. Instagram lets you take pictures with a nice touch. Pinterest is a collection of images you like.
To answer the post title: why do I love niche social media? Because if properly done they are so concrete it's obvious what they ask of you (and what they give in return, by the way). Startups, don't give us generic messages and please don't sell us the next Facebook. Find something we still don't do, help us do it and get out of the way.