This question was asked the other day in the Office Live Small Business Community.  The obvious answer is small business.  Your site can be a calling card for a brick-and-mortar business, you can sell, rent lease or contract out goods or services with your site, or you can use it for both.    They are not the only uses for a web site, however, and the variety of purposes grows every day.  Here are some examples we have seen here:

• Hobby, craft and special interest sites
• Political campaign sites
• Organization sites
• Movie review sites
• Neighborhood and community sites
• Family sites
• Authors’ book sites
• Sports fan sites
• College alum sites
• Teachers’ class sites
• Tutoring and lesson sites
• Résumé and curriculum vitae sites
• Special event sites
• Church and special ministry sites
• Class reunion sites
• Opinion and blogging sites
• Entertainment sites
• How-to/Do-it-yourself sites
• Tourist attraction sites
• Charity sites
• Reference and information sites
• Start a revolution sites (see Iran)

Because there are no limits to the purposes for a web site, this list will be a work in progress.  Every honest, legitimate venture or interest is allowed within the Microsoft Terms of Use guidelines.  Not even the sky is a limit here.  Sky sites, Weather sites, Astronomy sites, Milky Way sites...