Filters allow multimedia searching. Of course at that time I was also an employee. Soon Infoseek gave in to the pressure and re-introduced themselves as a free service. It was modeled after the Open Directory Project, otherwise known as DMOZ.org. Create a community of users to write short reviews on web sites they find and publish those results into your directory.
Guides have no reason to put much of an effort into the sites they submit or the reviews they write.
Here at Epinions, we write lengthy reviews on a wide range of products but we are also rewarded with click-through and income share rewards. If your going to give your users a huge amount of control related to your search results, then you should at least reward them for doing a good job. They do allow a user to choose to filter their search in case they are looking for just audio, video, or pictures. Plus in most cases, they do return some amount of results that are directly related to what your looking for. Metacrawling is simple.