Thanks to @barbaranixon for the inspiration with her Twitter lexicon blog post.
A few key terms you need to know to understand the Twitter world (Twittertopia?).
Tweet: Your 140-character (or shorter) message
Tweep: Someone you know on Twitter
@ : The symbol that precedes the name of a person you’re replying to
Twoops: Accidentally sending a direct (private) message publicly
Follow Poynter on Twitter @poynter.