In our case, and with many other educational sites, you can break down the directories. New web pages are posted more and more every day, but no one is taking down the old ones. Most commercial and government sites will have copyright information at the bottom of the home-page and some throughout the site. This date will tell you if your information is current. Look for a contact person.
Valid information is more likely to have a contact person included.
Quick tips to more effective search Guess one time. Have a favorite meta-search engine, but be prepared to use multiple engines. After choosing a favorite engine, learn it inside and out. Know how to use the menu's, site navigation, the boolean searches, understand the ranking system of the results, etc. Always use a second search engine.