Welcome to our irregular "Did you know?" column. First, you can mention somebody, adding at-sign to their username: @alice. This also works for groups: @support. Also, this handles punctuation, as you can see, so you can freely add dots, commas, exclamation signs etc. Second, when you want to reply to somebody's comment, you can click on "comment cloud" icon and their name will be added to the beginning of the text area. You can then click more comment clouds, and their username will be added, too. This will be particularly useful when mentions will be implemented.