Social media does count, and it does impact how recruits view the program and university. Are they coming on gatorchatter and reading the boards? Probably not, but it other people do, and they pick up on not the criticism, but the negativity. And then when they go out and speak about the gators its all negative. On many of the posts here there is a stark contrast between criticism and negativity. I have been on Bama and Vol boards, and yes there is plenty criticism on there, but it I don't hear derogatory names of their coaches or calling the staff idiots, looking at some inconsequential thing, like not wearing socks as an example of how "dumb" and "jackass" out coach is.
Even if you don't think message boards matter, you have to admit the possibility that it contributes to the general vibe around the program, as friends tell friends and so on and so on. If that is the case, then it is in your interest to keep things constructive.