I've been using Join for quite a while and I can't help but notice that the online SMS manager's layout is a bit strange (the new message icon is quite some distance away from the window's edge). Also, I'm not seeing all my messages from the interface. I'm seeing the last message I got from the preview, but when I click on the contact, the previous 8 or so messages just disappear.
Yes, they were MMS messages... oh goodness. I did not look at the to-do list for Join when I posted this. Sorry about that! I should have looked on the list before posting.