[Cerek]

Long before electronic communication became available, it was somewhat standard practice to write "(haha)" in a handwritten letter after you had said something in a joking fashion. Of course, one of my English teachers pointed out that this was very poor form, as the joke should be funny enough to be recognized as such without the reader having to be told to laugh. Then again, the writer could use it to denote that he/she was saying something sarcastically.

The "LOL" abbreviation is used much the same way, only in response to certain commments. The person will type "LOL" to show that he/she thought a particular comment was funny or they may also use it in a sarcastic manner when admonishing the original poster that they felt a comment or joke had been made in bad taste.

I personally haven't noticed it being used to an excessive degree. It is usually appropriate in the threads where it does occur. The particular comment may not seem funny to you, but as Kakero mentioned above, different people think different things are funny. Usually the "LOL" is used to denote something is amusing while "ROTFLMAO" is used when somebody thinks something is really funny (usually means the reader actually did "laugh out loud" at the comment made). And of course, IM and emails have generated their own genre of abbreviations (though I have to admit that "ROTFLMAOTIDD" is new to me).