Google, a popular search engine, is a tool for finding resources on the World Wide Web. Google scans web pages to find instances of the keywords you have entered in the search box.
MSN Search was a search engine by Microsoft that comprised a search engine, index, and web crawler. As of September 12, 2006, MSN Search is now Windows Live Search.
Meta Tags are information placed in the HTML header of a Web page, providing information that is not visible to browsers but are there for the sole use of search engine spiders. These (numerous) tags contain various information that the site owner wants to deliver to these spiders.