Ability to restrict sites from the search results in my preferences (Google doesn't seem to be able to restrict certain obvious spam names databases from results, so let me do so myself. It would be best if there could be filter lists that are maintained by various communities that I could choose to apply. I can imagine there are technical hurdles to overcome to make this a reality).
Then I posted about how Google should improve, again a year later
Let me remove web sites from my default searches. I would imagine this could even be used to help Google’s normal search results by getting a sense of sites huge numbers of people “block” The same spam sites show up for searches and I would rather block them if Google can’t figure out how to do so.
Hide sites to find more of what you want
We’re adding this feature because we believe giving you control over the results you find will provide an even more personalized and enjoyable experience on Google. In addition, while we’re not currently using the domains people block as a signal in ranking, we’ll look at the data and see whether it would be useful as we continue to evaluate and improve our search results in the future.
Better later than never. But 6 internet years is a long time to wait.
Related: Google Social Circle Results - Search Share Data, Checking the ACSI - find management content online