Directory owners: are you linking to malware sites? How can you check?

[Obelia]

Replace example.com at the end of this url with your own website:

http://www.siteadvisor.com/sites/example.com

This is McAfee's Site Advisor, and it flags websites that host malware or send spam. It also flags websites which link to undesirable places. If you run a directory with more than a few thousand links, the chances are high that some of them will be dodgy. Because many sites hosting viruses and spyware do so without realising they have been hacked, or because their 3rd-party advertising is distributing malware.

We can spider for 404s and other things we don't want to see, like parked pages. But is there any way to check large numbers of urls for malware on a regular basis?