I know that we have to be careful how much we tax the servers for HN, but I thought of a simplistic and low-processing overhead for allowing users to block certain domains.

1) Allow us to input a list of domains we don't want to see links to.

Ex: csmonitor.com, godaddy.com, codinghorror.com etc.

2) Modify the item listings on the various listing pages to include a class that is the url's domain.

Ex: So if the link's url is http://x.com/asdfasdf the link listing would be class 'x.com'

3) Implement a basic css command generated on page load that adds our domains listed in part 1 and adds a 'display: none;' for them.

4) Win!