Hmmm...Matt's comments are interesting, but are they relevant to our tools? As you know from using our forums, you only get e-mail if you request alerts and, just like the blog software he's using, forum posts here are published instantaneously on the web. I can't imagine that's not true of his forums as well.
Maybe forums are too structured, being organized into topics for discussion?
As far as whether or not rating systems might deter people from posting ... evidence from sites such as Slashdot suggest that there's no rating system in existence that will stop people from making fools of themselves.
Of course widely read internet forums like Slashdot are virtually anonymous ... it might be different in an educational environment where many people know each other and one might be embarassed by a low rating.
As Roc says, allowing the poster to turn off ratings on their contribution would be possible.
Another possibility might be to only allow the rating of "exceptional" ... not having one's contribution rated at all in this context might not be as negative as (say) getting one star out of five.
Questions like these are why a general ratings package needs to be ... generalized.
