As of early September, the Enter key submits comments on most sites. I know there was some grumbling about this functionality at first, which is normal for UI changes, but it seems like most people have gotten comfortable with it now. It still hasn't been carried over to Area 51, though. Is this intentional, or an oversight? I, for one, would like to be able to submit A51 comments with Enter, now that I'm used to the behavior.
We pulled in the press-enter-to-submit-comment change, so the Area 51 comment form has the same behavior as the rest of the network now.