Here are some techniques for figuring out the key information about a Web site.

• Whois: check a WHOIS service to find out who owns and administers a particular domain. The NikkelWHois add-on for Firefox lets you check this info for the current site, and you can check the InterNIC site directly.
• BuiltWith: this service tells you about the Web server environment for the specified domain name.
• Google: use Google to find out various things about a Web site, including which site pages are indexed (using "site:www.mendocinofun.com"), and which other sites link to a Web site (using "link:www.mendocinofun.com").
• SearchStatus (Firefox add-on): provides a lot of SEO info
• MetaTags Sidebar (Firefox add-on): more meta info
• Webconfs.com SEO Toolset: several great tools for assessing a site
• SiteScore : scores sites based on a bunch of factors
• Compete.com : compare site traffic (with caveats)
• SmartPageRank : site evaluation