As you may know, there are a number of websites (such as
wenda.io) that scrape content from StackOverflow (and other StackExchange sites). I couldn’t care less that they do this, and indeed they are at perfect liberty to do so as long as they attribute where they got it from (I’ve also done my fair share of reporting those sites that don’t do this), except these sites are polluting my search results.
The problem is that there are dozens of these sites, with new ones seeming to appear every day. They often appear right beside the corresponding Stack Overflow page, but sometimes they don’t. The sites themselves are usually terribly formatted and difficult to use, and of course don't have all the “related” boxes that I find super useful on Stack Overflow (though they have their own poor imitations). Furthermore, I don’t want to support these sites by using them.
Is there a simple way to exclude these scraper sites from Google search results? (I'd be happy if you could find a solution for DuckDuckGo too.) Note that I don't want only SO search results, because then that would exclude all the other non-SO stuff that also helps me.
Here’s an example search on DuckDuckGo (as of 4 Sept 2015) where 11 of the 30 results on the first page are from Stack Overflow scrapers. Google has quite a few Stack Overflow scrapers too, though it also has lot of results that don’t show up on DuckDuckGo that are mixed in.
Edit: I was looking for solutions specifically for StackExchange sites, and more specifically, StackOverflow. The question that is marked as a duplicate is similar enough that it could be a duplicate, depending on if specificity is taken into account (but it certainly doesn't answer my question, but then, neither do any of the answers here).