Google is not blocking domains users tell it to from search results.
Early last year, in Google's efforts clean up the quality of its search results, the search engine launched a feature that let users block domains from search results that they didn't want to see in their future results. Tired of some content farm showing up every time you search for something? Go ahead and tell Google you don't want results from that domain, and you should be all set.
Unfortunately (or perhaps fortunately for any sites frequently being blocked), Google doesn't seem to be acknowledging these requests from users any longer. It's unclear at this point whether this is or intentional or not, but it seems to be on the surface.
Barry Schwartz at Search Engine Roundtable points to a Google Web Search help thread pointing out that users have been experiencing this issue for sometime, and was able to confirm that Google was not showing the feature in search results for him, and that blocking a site from Google's "Blocked Sites" settings page also did not work.
We also confirmed this on our end. The feature in the actual results simply is not there, and blocking from the settings just isn't working. I searched "how to tie a tie," and blocked a domain from the settings. The settings page listed the domain as blocked afterwards, but the domain still appeared in the search results.
Note: Nothing personal against the site in the screenshot. Just a random test, which I removed from the blocked list.
We've reached out to Google for comment, and will update accordingly.
Google has been quietly making other changes to Search. Yesterday, we told you about Google's changes to SafeSearch results, which were not accompanied by any announcement.