A friend of mine and I were emailing recently, and she cursed in one of her emails. I asked her to avoid that kind of language when talking to me in the future, and she said, "But it's just in writing! It doesn't count if you don't say it out loud!" My personal opinion is that yes, it does count when you use a bad word in writing. All the negative effects are still in place, and you're still using the word, if not saying it out loud.
Some members have told me that they and their friends would never say a bad word out loud, but when writing they're not so picky. Put it this way: if you would never bully a person in real life, would you cyber bully them?
A few days later, the same friend emailed me and used the acronym LMAO, which stands for "laughing my a** off." I told her that I would really prefer if she doesn't use that kind of language, and she said, "But I didn't even write out the word!" Even if she didn't use the word, I know what word she would have said had she written the phrase out, so to me, it counts as cursing. (When I want to use something to the effect of LMAO, I either do LOL, ROFL, or LMTO (laughing my tushy off!!).)
So, to sum up, using bad words in writing still counts as cursing, and using acronyms that have bad words in them also counts as cursing.