I often wonder what the difference is between people who write "haha" and those who use LOL. Though emoticons provide an ample array of graphic representations for various emotional states of being, initialisms in internet slang like RFL (rolling on floor laughing), LOL (in capital letters for emphasis) and haha are the most common performative utterances used to describe states of jubilation. Personally I find the locution "haha" to be ineffective and rather "testicular" to use a favored Egyptian expression. I only use "haha" when the desired effect is sarcasm, and even then I make sure to add a third ha as I find two has alone to be too weak to transmit a sufficient degree of denigration. In expressing spontaneous rapture I consider LOL to be most effective and more genuine in that it informs the interlocutor of the subject's state rather than merely describe it through onomatopoeia.
I must confess that I sometimes use "hehe" to impress a sneaky-coy temperament (note that in this case two hes are sufficient), this is because the e in the hehe transmits a softer less imposing sound.
Anyway, haha sounds more like the braying of a donkey than the laughter of a human being.