I think it has started to happen. What can we do about it? If identities are being tracked/recorded/noted, anything we have posted up to this point is fair game. What are the suggestions?
You can't do anything about anything libelous you might have already posted, just like you can't do anything about any banks you might have robbed in the past.
Eventually the statute of limitations will protect you.
The chances of anyone here getting sued are pretty minimal, unless it's an orchestrated attack by the Democrat party. While there have been many attacks on individuals that might be judged libelous, almost all fall into the category of being somewhat debatable, or expressions of opinion. And then there's the question of whether someone's reputation has truly been damaged as a result of the post. How can Bill Clinton's reputation be hurt at this website?
Like it or not, people are skating on thinner ice on the Schiavo threads. The ice isn't much thicker on the Kobe threads or the Laci Peterson threads. In a lot of instances, posters here are risking a suit which they could lose.
It probably won't happen, simply because it won't be noticed, or the amount of the award recoverable isn't worth the trouble of filing a suit.
But it remains a possibility. Nobody is immune to a libel suit simply because they're posting under a screen name.