Prospects use search engines through out the buying cycle :
Research a problem or technology need
Understand the value of ROI for a specific solution
Learn about a vendors reputation
Discover new solution vendors I may not be aware of
Find peer discussions or reviews of products
Discover technology problems I wasn’t aware of
Find white papers, case studies or success stories
Find the price of a specific product or service
Explore specific brands of technology products
Find information on a particular service or vendor
Find product reviews
Understand a product’s features or specifications
Source: Google / Tech Target : How IT Pros Search Online During Purchase Process