From Search Engine Optimization:
The SEO Toolbar version 2 will simplify and enhance your search engine optimization efforts and overall Internet surfing experience so much that you'll wonder how you ever lived without it! Web Searches - Perform web searches with 11 major search engines. Ranking - Get ranking for a domain/keyword in Yahoo!, MSN, Google individually or all at once. Checks top 40 in each engine. Keyword Density - Checks a page for an occurrence of a keyword and reports back percentage in title, meta, and body HTML Validation - uses W3C to validate the current page, all in one easy click Site Analyzer - checks a URL for internal links and images, as well as a count of those occurrences, including link/alt text. Engine Data - Google (internal/external) links, Google cache date, Yahoo! (internal/external) links, MSN (internal/external) links, Dmoz, Google Directory, Yahoo! Directory inclusion Network Data--URL IP(s), Load Time, Ping, Whois data, Response Header.