I used to use several of these, because different friends had different addresses and preferred the look-and-feel of a particular one. And then people started shifting to Orkut and FB and Twitter and Whatsapp and Viber and Snapchat.
It slowly got lonelier and lonelier. After all, in this always-connected world, who needs those old IM platforms when the smartphone apps are so much better? (Well, people who don't use smartphones, for one!)
I still use one of the old ones, mostly for work. Till not so very long ago, there used to be a regular flow of friends on it. But slowly slowly, the logged-in list has been growing shorter and shorter, till now it's only populated by those who know it's the best way to reach me for conversations (when they can't talk, of course).
I guess the reasoning is not without logic - why bother to log in on multiple platforms when nearly everybody is on the two-three big ones? And for those who aren't, well, tough. In a world where we have too many friends in too many places and too little time, a few are bound to slip through the crack, right? And if they do, and you don't really miss them, then obviously they didn't matter to you that much, yes?
Whatever. All I know is that I have to continually log on to bloody FB to keep tabs on my friends.
And let's not even get started about emails.