Also, a variable of Boolean type or a function with Boolean arguments or result. The only decent way to find what you're looking for, whether it's pictures of the Potomac, a Web site about Robert E. Lee, a friend's email address, or newsgroups about sled dogs, is to use a search engine. At their simplest, search engines are programs on Web sites that let you type in a word or phrase, press a button, and see a list of other sites that contain the word or phrase you chose. At their most advanced, they offer sophisticated ways of narrowing your searches to find exactly what you want without cramming your screen full of irrelevant links. The most famous and popular search engine is probably Yahoo, but there's also Lycos, HotBot, Alta Vista, Excite, and a whole bunch more.
None is clearly better than the rest.
Each has its own quirks and makes claims about its superiority. Your best bet is to try several and stick with the two or three that you feel most comfortable using. These can be interesting to browse, but active searches often work better if you're looking for something specific. When it comes to search functions, all the big search engines have similar options. In general, be as specific as you can.