With the external listing type, there is often extreme variation in what they'll pick up. Try more than one for specific searches. The Yellow Pages of the web. Huge numbers of entries. Rating system and reviews of all sites listed, so there are not as many sites as, say, Yahoo.
Interface is easy to use but frustrating.
And the display only shows 10 entries at a time. Returns thousands of pages with many searches. Not all posts show up though, even in groups where other posts show. Keeps a database going back to spring 1995. Misses a lot of posts.