When anyone uses a hashtag (simply a way for people to search for tweets that have a common topic and to begin a conversation) on a website, text message, or anything that does not pertain to Twitter. This is quite annoying considering hashtagging only works on Twitter.
(In a text message)
Guy: Hey want to go see Paranormal Activity 3?
Girl: I can't, I have to work :( #IHateMyJob
Guy: That doesn't work on text messages, only Twitter.
Girl: But I do it on Facebook all the time! #FreakingOut
Guy: Oh my God you're an idiot.