I think blog-goers generally care more about how they are perceived as well. I think the concept of reciprocation limits people obnoxiousness here. At Slashdot they are mainly commenting on news and don't mind dumping on it, whereas here people create their own content and would prefer not to be dumped on.

It is much less attractive to become a troll magnet here, and I think there will be less trolling. Anyway, when the topics are of limited scope, people tend to get bored and ad-lib more. Here there is no end to the material.

Slashdot is a site I do not visit and I despise it for its anti-Microsoft bias.

I'm with Tech Cat here. It seems like it's ran by teens with no value of money or the real world for me to enjoy it, although sometimes I do enjoy reading the trolls there. In fact, I'd say that's the only positive thing about Slashdot.

Several more observations:
Slashdot is good for link-collection, as most people's comments are short remarks on various tech news or trendy links.
Plastic.com tries to be slashdot for all other subjects and news, hence tend to be less focused and less interesting.
On JoeUser, I find lots of interesting topics that are not necessarily recent news, but issues of long term social relevance.
They tend to be good and thoughtful articles, better than most personal blogs on the net. Comment on these are usually insightful.
So overall, I am finding JoeUser a much valuable 'think-tank' for discussion than anywhere else on the net.