For example, recently there was the thing with Rob Malda's resume. The entire thread on that was rather derailed into either sucking up to Rob, or saying Slashdot is full of trolls.
Or rather, it had a rather unfavorable signal to noise ratio. I tried to vote comments accordingly, but it didn't really seem to help.
[1] Tried to stick up for FOSS and expose Microsoft/Mono for what it really is, got downvoted for doing the right thing. Oh well, the trolls got me, not really a big deal.