It seems that it might be more helpful to whitelist sites. The web grows too quickly, and the mass of spam sites overwhelmingly so. If I had some way to blacklist sites, I'd end up spending a lot of time doing so. In fact, it could quickly take up most of my search time.

If, though, we could whitelist sites, it seems that results would get cleaner faster. I don't care about how many bad sites are out there, as long as helpful sites make it to the top. Plus, I typically use just a few sites to access reliable information anyway (the number's about 7, right?), so if I can whitelist results from those sites, I'll probably find my desired content more quickly.

What about the case when there are 30 spam sites listed before 1 good site? That hasn't happened too often for me. Instead, the results I'm looking for are usually just 4 or 5 spots down the front page, and very occasionally on the second page.

White listing seems like it would still be faster and easier for now.