Since the new design, I have (multiple times) found myself unintentionally at a poster's profile while just reading a discussion. It's as if I've clicked on their username, but I haven't. I have not yet been able to reproduce exactly what it is that causes this to happen, but it's something I *never* observed with the old design. I'm using Firefox on Windows 7 if it's relevant.
ETA: I figured it out. I guess it (sortof) makes sense. It happens when I am opening a closed comment on a thread. I am apparently clicking on the user name rather than the "comment fragment". That brings me to the user profile, rather than simply opening the comment. Is this the way it used to work? Before, didn't you simply click on the name to open it up? I understand the logic, but it seems like going to the user profile is *rarely* going to be what someone really wants to do in this situation.