I recently found out about a service called Website Grader. You give it a URL and it analyzes that website for SEO statistics. allQoo.com scores 82 out of 100, not too bad.
Besides the badge the checking includes a whole bunch of things in two groups: on-page seo and off-page seo. In the on-page section, there are basic stuff like metadata, heading summary… it looks into image summary, interior page analysis and, very impressedly, readability Level.
The Off-Page SEO statistics include Domain Info, Google PageRank, Google Indexed Pages, Last Google Crawl Date, Traffic Rank, Inbound Links, DMOZ Directory, Yahoo! Directory and ZoomInfo.
It also has Blogosphere statistics (Blog Analysis, Blog Ranking and Recent Blog Articles), Converting Qualified Visitors to Leads (RSS Feed and Conversion Form) and Competitive Intelligence (Keyword Grader, Score Summary and Historical Data Available).
This much is free, but there are more features available like comparing historical data if you sign up for the paid service. It doesn’t say anywhere on their website how much it costs, which usually means it’s expensive.
Website Grader summarizes all of this information into a Website Grade – a single number that represents how well you’re doing. You can then get a widget to put on your website that displays your grade.
If you want not only free tools but also making money from your web sites, LinkShare is a good marketplace to get paying affiliate programs: