As a non-twitter-using software engineer, when I land on a twitter page, I still find it fairly intimidating and requiring special knowledge. For example, why is there a dot before the @ in your example? (I actually know the answer to that because I looked it up once, but it's totally not obvious.) What's with all the slashes in numbered lists?

Because of the character limit, people use a lot of abbreviations and shorthand that I can usually figure out with some puzzling, but I shouldn't have to do that.

I still see url-shortener urls all over on twitter, when I should just see regular urls.

These may be minor points, but it adds up to giving off the feeling that there's an in-crowd and I'm not invited. It is much better than it was a few years ago, though, so maybe it'll get there.

(I'm not even getting into the difficulty of actually following a conversation on twitter! Reverse-chronological order plus the lack of linking replies to their parent messages make it nearly impossible, but that's a well-known issue.)