What do you mean? In the comments? Can you give an example, just tried a username with a '.' in it and it seemed to work.
It's weird, i tried with other usernames with it but it worked but a few I tried and didn't. I can't find the particular guys name anymore, he commented on my track and I tried to reply and it was like (you cannot reply with a url)
Ah, must have had '.com' or something. Will look into that. If you do find the username let us know will help to debug.
Thanks for bringing this to our attention, turned out to be filtering a lot of names mistaking them to be urls when in fact they weren't. Pushing out a fix now, let us know if you have anymore issues..