Acronym for "tell it to your blog". This is used in forums and can be said aloud if you'd like. It is told to drama queens and people generally being overly dramatic. It can also be said if people are talking for themselves to be heard and aren't contributing to anything when they're speaking/typing.
Jessica: So I bought three barbie dolls and then I combed their hair for six hours. They're really pretty just like me. I wish somebody would love me.
Jessica: What's that mean?
Arthur: It means I think you're great.