I have gone on and on about anonymous message boards here before and they are a problem, but I think a new problem we as coaches are dealing with is social networking sites such as facebook and twitter. On anonymous message boards, you don't know who is talking and who is not, but on facebook you can go straight to the source of some of this stuff. Unless that person has blocked off their "wall" you can read what they post, and it can usually lead you into knowing more than you do and sometimes more than you want to know.
We have a rule that we implemented this past season about not speaking negatively of the school, administration, their teammates, or the coaching staff on facebook or twitter. If they do they will be dealt with accordingly. It is the same with their language on these sites. To me, if they are on facebook using profanity, it is the exact same thing and probably worse than standing around at the local restaurant using the same language. Even though you are online, you are in public and must act accordingly to what is proper. Because you do represent more than yourself in public if you are playing basketball, and that representation carries over online.
So what do I do? Unfortunately, I will check out a few sites from time to time, but even more unfortunate is that many people are more than willing to let me know what is being said or how it is being said online. Then I check it out, and the first time I talk to them "council" them so to speak and that has so far ended it. I think most kids who play for us respect that the players and coaches are working hard and when they realize that it is making others look bad they are quick to stop doing so.
But, like technology in schools, these things aren't going anywhere soon, so we have to either learn to deal with it or ignore it completely. I may come to the point where I will ignore it, but I am not there yet.