I am currently self-hosting a meta search engine instance (searxng), which allows me combine searches from different engines (e.g. Google, Bing, Yahoo, etc), but also to filter out websites that I don't want to show up.
The only website to make my blacklist so far is slant.co (useless SEO-riddled site that always comes up when I search for software comparisons). I also automatically redirect all reddit.com links to old.reddit.com.
I'm looking to expand this list. So, which websites do you blacklist? Either using software, or just mentally.
I've been using a Firefox extension instead that has fairly good filters by default, because I kept getting crap results when looking at technical questions (ie. landing on over-simplified examples without details instead of official documentation).
https://addons.mozilla.org/en-US/firefox/addon/ublacklist/
They publish some subscription lists of things blocked that you can chose from: splogs of GitHub/Stack overflow, Pinterest... And then you can add custom blocks directly from your results list (Quora...). It can be a nice point to start with to use their filter even out of the extension imo.