With any written text, it's sometimes difficult to interpret one's mind since there's no facial expression, mood indicator or tone. The exact same sentence can be used to encourage someone or to tell him off. A good example is someone writing a word or two just to catch attention on that word but be seen by someone else as yelling.
I agree that the "LOL" can be an eyesore in forums but I use it from time to time to show that my post is a positive one and that I'm not þ!$$ɘd since there's no mood indicator system or smileys or whatever (...and inserting media linked to my Photobucket account for smiley usage is a little painstaking for me).
(I'm not angry here... LOL... oops! sorry!)
Rob