You can browse Yahoo! by simply clicking on the various categories listed on each page. Search Yahoo! by entering a word (or, a few words) into the seach box that appears on every page in the directory.Combine the two strategies and you can "browse and then search" or "search and then browse.
Inside the Search Machine: Yahoo! categories, web sites listed in Yahoo! and web pages indexed by Inktomi...
For the first two of these, Yahoo! searches for matches in its database and then ranks the results in order of most relevant to least relevant. Some of the factors that affect relevancy are:  the number of search words matched. 
The more words matched, the higher the rank. exact word matches. These are ranked higher than approximate matches. where in an entry the search words were found. A match in the title of a site is ranked higher than a match in the comments or the URL.
Example: You're looking for People Magazine online. Instead of browsing through the News and Media category, finding Magazines, and then finding the People Magazine in the alphabetical list, just type "people magazine" into any search box (you don't need to capitalize the words and you don't need quotes).