I don't understand not using punctuation. I think it would be hard to not use it at all.

I've seen people that didn't use punctuation. But I don't find that nearly as annoying as really long hash tags. Like #Ijustateapretzelcoveredincheesesauce. Try reading some hash tag like that and you can end up getting really weird words out of it. It's just about as bad as trying to read something written by someone who doesn't speak the same language at all. Yet for some reason some people want to put as many words into a single hash tag as possible. It's one of those things that really makes no sense to me.