One is that they’re trendy (even if they don't want to admit it). People go where the people are, people like to follow trends yet earn to be first, so they often gravitate to the latest and greatest like snap chat and Instagram. These platforms are no better than Twitter, although they serve a unique offering compared to the Twitter platform, it's not new, people aren't intrigued, they know Twitter. People are excited about new.
The second is people have created a bad social experience for themselves have learned from these behaviors and now better curate their social accounts. They're more selective. The like and follow are becoming a bit more cherished. For example most people are connected to their families, their colleagues, even their managers and professors on Facebook, although networking is great and it seemed like a great idea at the time, we bet there are many of times these people have kept you from sharing that funny photo, or made you think twice about posting that status update. We're not advocating you shouldn't think before you post, just like you should think before you speak, however this keeps many people from posting updates they may once have, eliminating their experience on this platform. Sure there are options to only share the posts with certain people, but who has time to set up all these groups?
Learning Lesson? For companies… it's great to follow trends, beware of them and perhaps have a presence on these social platforms, but don't chase them, and don't neglect those that have become staple platforms to the eyes of your users. And for everyone else… curate your social, delete that person you would avoid if you ran into at the super market, unlike that brand who's posts don't excite you, and let go of the social feelings, it's your experience, if these people are offend by your desire to curate your online social experience well there's a someecard for that.