If you build it, will they come? This is one of the fundamental questions anybody creating a Web site has to confront, whether you're a business person, a Web professional or a home user. One of the fundamental ways to ensure people do come, and return, is to make the content of your site as appealing and as accessible as possible. A new study by Forrester Research, an information technology market research firm in Cambridge, Mass., examines just what people most value in a Web site. The bottom line: People seek substance over style, usefulness over flash. They want to get what they want quickly.