In summary: I mean... is that the @ symbol is used to indicate that the message is directed at the person who is mentioned in the tweet.It's more visible than Dave: and it clearly indicates a completely new comment. I know I use it. Only when quoting multiple people and I don't A) feel like multiquoting or B)making my post look all cluttered and filled with quote boxes. The person knows what they said so all I have to tell them is that this comment is directed at what they said.I don't see what the problem is with it, it's not hard to understand at all. @=at, @Dave means at Dave. It's more visible than Dave: