Lately I've seen this happen where sometimes I'll type an answer, click "Submit Reply" and the "Submit Reply" button is dimmed to indicate I've clicked it, yet the post doesn't seem to be added (the text entry box stays open). If I refresh the page then I realize that the post had been added. When this happens, I can tell it's happening to others as well because they must click "Submit Reply" again, resulting in double or triple posts.