Funny.
Here's one from Temple University Mathemaician John Paulos. His quote about Internet Forums, which I think succinctly sums up their general value, applies to most, but not all -- with this site being an exception most of the time.
"..online denizens form little groups that spend a lot of time excoriating, but not otherwise responding to, opposing groups. They endorse each other’s truisms and denounce those of others....Only a brief visit to these sites is needed to see that a more accurate description of them would be rant rooms."
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