[dtwest]

Long simply means taking a position that would benefit if the stock/currency/commodity/bond/etc goes up in value. Similarly, being short generally means the opposite (although in specific situations it can mean selling something you do not own, like a stock, with the intention of buying it back later for a lower price). The terminology isn't limited to stocks, investors talk about being long currencies all the time.

Hope this clears up some of the confusion.