No, it's not particular hard, but it will make the problem worse. Why? 99% of users are non-tech oriented. Those users will not really be aware of the specific problems with the search results, they won't understand the concept of a good vs bad result and they certainly won't bother to tweak/ban/filter their results. The 1% that do care and are currently being vocal about it will start filtering their results and the…
What I think really needs to be exploited is a ring of trust type aspect, I'd like to have the Hackernews ring where all us on here work together to remove the spam from our results and let's Google see what are taking out, maybe that will help them improve their algorithms.