Google SERP: new function to block unwanted domains

Google has just announced a new function to block unwanted sites in SERPs. With this function all hits of blocked domains by a user will be filtered out of the user's future SERPs. The blocked domains can be administrated via personal search settings. If there are filtered hits in the SERP an according information is shown.

Google sees this as a further step toward customized search results. The question however is in what way the ranking of the concerning sites will be affected. Possibly sites that are blocked by many users will be punished and downgraded. After all the clicks of a big range of users give a valuable hint concerning a site's popularity. The changes will first be rolled out for google.com and afterwards for the remaining regions.