The issue I have is that if the topic could even remotely sell me something, those selling or reviewing the thing sold in order to sell it will be the only results. The communities actually interested and talking about the things have disappeared from the results.
One trick that works for some topics is to limit your search to a custom time range like pre 2005 or so. Specifically this only works for information that would have been available then, but when that is the case you can avoid a ton of modern spam.
