What is being done to remove “no results” pages?

Matt's answer:
Today’s question comes from Toronto, where MrTVTL wants to know, what is being done to detect and remove results from larger sites when they don’t have unique content that is relevant to a query? For example, yelp.com results with no reviews, Facebook business pages that weren’t actually created by the business. I like that question, but I wouldn’t just restrict it to larger sites. In general, we look at the value add or whether there is some compelling value add even at a page level, and we try to write algorithms to reflect that. But it is the case that sometimes you will find pages that get indexed at, say, zero reviews found. And so there’s basically no content to actually base your opinion on when you visit that page. So even starting back in 2009, I found a blog post that I did– give Google feedback on no results pages. And so it was a complaint even back then. People didn’t like having empty review sites, where you click through and it says there is no reviews for that product. So either do a spam report or show up at the forum or you might even still be able to use the form that I mentioned in that 2009 blog post. But basically, we are happy to say, look, if you are even doing search, and there’s no search results on that page, that’s the sort of thing that users get really angry about, they complain about. And so that is the sort of thing that, under our technical guidelines, if you look at our quality guidelines, we do say that we’re willing to prune out those sort of search results. So if you see examples where you land on a page, and it’s really frustrating, because it’s either more search results that are just scraped or there are zero reviews or those sorts of things, let us know. And we actually do have the ability to typically match those pages and then make sure that those pages don’t show up. And so we’re happy to get reports of that sort of thing. Anybody that wants to mention concrete examples like that– they annoy us too, and they annoy our users even more. And so we’re happy to clean those out.
by Matt Cutts - Google's Head of Search Quality Team