I suggest you start there first. The first way is better for basic topics and the best way to start your search. It is also way better for browsing topic catagories. You are more likely to get quality pages this way. The second way is best for finding obscure topics, people's names, or doing very specialized searches.
Every site operates differently.
Yahoo is the best organized I've seen, with the best search engine, of the local listing type. 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.