Google has launched its own personal blocklist for the personal banning of dodgy websites from your search-results. This only works with the Google Chrome browser. Blocked sites are shared with Google. There’s no way to import a pre-existing list, or export your list to share with others.

Firefox users already have the excellent (and private) Greasemonkey script Noise Reduction for Google & Bing which also works with Bing. And with this Firefox script you can import a blocking list that you may have used previously with other software (such as SurfClarity).