New thing time! You can now edit your own comments.

Hover over your own comment to reveal the pencil icon in the upper right:

editing-pencil

Click it to edit the comment:

editing-comment

Make your changes (Markdown!) then click Update Comment to save it or Cancel to bail.

Fairly obvious benefits =). We think it will be particularly useful for those just learning Markdown, as you can give it a shot and fix up mistakes rather than be scared of it and not use it.