Ah, so it's actually not entirely removing blacklisted results, it's just condensing those results. Personally, I think I'd be more interested in nabakin's idea of editing the query before it gets sent to Google.
Although - like zargon says in a top-level comment - this clearly should just be built into search engines themselves. The only semi-legitimate reason I can think of that they wouldn't be is that results for a given query would be even less reproducible than they already are from person-to-person. But since Google already "personalizes" results, I don't think that's really a factor for them. They could just have a little button at the bottom that says "3 results from sites you've blacklisted - wanna see them?" or whatever.
Since the results are customized anyway, they should also give us a way to assign more or less weight to a result and learn from that for future search queries.
Google News does this on every link (Hide stories from XXX, More stories like this, Fewer stories like this) so clearly the feature exists.
I am thinking about more customization, especially this that allows the user to 1. suppress (like now) or 2. remove the results entirely. But in my defence, it was a weekend project for a noob like me.
Although - like zargon says in a top-level comment - this clearly should just be built into search engines themselves. The only semi-legitimate reason I can think of that they wouldn't be is that results for a given query would be even less reproducible than they already are from person-to-person. But since Google already "personalizes" results, I don't think that's really a factor for them. They could just have a little button at the bottom that says "3 results from sites you've blacklisted - wanna see them?" or whatever.