A lot of college teams have banned their players from Twitter and with good reason. Too many kids tend to tweet without thinking (or while drinking) and fail to realize that there are thousands of people watching their every tweet. Any and every misstep is caught, retweeted, and used as fodder for late night jokes and bloggers everywhere.
So it is easy to see why coaches would not want to have their players on twitter--to protect them from themselves! However, while there are many guys that could use that protection (right Johnny Manziel?) there is good reason to allow and even encourage guys to tweet.
It's an easy way to keep tabs on guys.
Think about it. College athletes are essentially still kids. Kids are going to act like kids even though they are representing multi-million college football programs. It doesn't matter that their actions do not put the program in a favorable light. They don't think that far ahead.
This works. I used to coach a high school rug...