I think for this site, in particular, or other advice forums, a troll can also be someone who purposefully posts inaccurate or untrue information. For whatever reason. I honestly don't know why someone would lie to someone else who is looking for help.
It's just unscrupulous, harmful, and only going to cause problems. For the site overall, it brings down our reputation. Anyone who's been following the "drama" about AC knows what I'm talking about.