It does, doesn't it? I've sent private messages to people. On a hubbers profile page, just under their photo, there's a button, with an envelope icon, that says 'Contact Lady Wordsmith' or whoever they are. I use that.
Addendum: Oh sorry! When I came to answer this question it showed me no other answers, so I thought I was the first!! I am now editing my answer, lol. I find this way of messaging to be fine - it's fast enough. You could always befriend a hubber on a social networking site if you wanted to chat to them more instantly.