Search engines are machine indexed. That means that you will get more hits but you might have to wade through your results to find what you really need.
Directories are human indexed.
That means that you are searching fewer sites, but your search results may be more relevant to your needs. The downfall of metaseach engines is that different search engines often use different search syntax which might lead to a false report of no hits. ConnectNet - Find a library near you that offers Internet access. This tutorial was designed by the Library Network Technology Committee of the State of Michigan for people who have never used a computer before.