Previously we had reviewed a web service called ValueMyWeb, which gives the total worth of a website. ReviewMyWeb is a similar service which stacks you up against your competitors and gives rating based on Google, Yahoo, Blogs, and other key channels like Web 2.0, SEO, PPC, Social News, Blogs and may more. You can submit upto 3 sites at a time, including your site. The comparison chart is not generated quickly, instead you need to provide your email and the report link is emailed to you.
The comparison is based on traffic ranks, SEO, Search Engines back links, social media analysis and overall site analysis. Here is an analysis of Facebook, Friendster and Myspace.
Finally it compares the overall rating and tells you whether the site the over performing or under performing compared to the competition. It also suggests improvements areas for your blog. ReviewMyBlog is a pretty decent service to compare your website with the competitors.