here's an article from searchengineland about google "bringing back" this feature. the article is dated 2011.
When you do a search in Google, the search results will show a new link near the “Cache” link when you click a result and then return to Google. The link that Google adds to the search results reads “Block all example.com results.” Clicking on that will allow you to block the site from showing up in the Google results.
in the era of ever-increasing seo-optimized spam hellsites, the option to create a personal blocklist of "junk domains" would be rather useful.
... which is why the feature is long gone, of course. there's a "remove result" option, but that's for literally removing it (because it's illegal or otherwise against google terms), not to curate your own results.
