There has been a bit of an issue with some swickis where the blocking of websites has not been working as it should.
We are still refining how it works behind the scenes but we think the current functionality is pretty useful as it stands.
As moderator of a swicki you can choose to block just one webpage or the entire domain and then they will never show up in your search results again. There is a link at the bottom of search results page that allow you to see deletions you have made and undo them. Let us know if you have any issues with it.