If you see spam in Google search results, you can report it to Google using the Report a Spam Result link. Google claims that they take these allegations seriously and investigates them to see if the results are spammy.
A WebProWorld Forums member is wondering, though, if Google is taking heed to his spam report. According to him, there is one company that has multiple websites with duplicate content and they are dominating the front page of the SERPs. How can he report this?
Well, perhaps he cannot. In fact, forum members think that he should focus on "real" spam and not competitive spam, like copyright infringement and trademark issues. Apparently, Google just doesn't take action on all of these spam requests, because there are probably far too many of them.
Ditto on Google doing nothing. I made a number of reports of sites that posted giberish containing my best keywords. Google never acknowledged getting the reports and never took action. I wasted my time.
Forum discussion continues at WebProWorld.