How certain things make "trending topics" on Twitter also baffle me. For a while there Justin Beiber was there every day ... why?

I don't mind when people I have never heard of are "trending topics" - as they are sometimes political figures from countries I don't know a lot about, or sports I don't follow, but when a pop singer gets months worth of attention for apparently, well, existing ...
I'm baffled by anyones need to "twitter". Period. If people did not have a voyeuristic need to peep into others lives then 'the media', Facebook and Twitter would not exist.