Windows 7 Tip: 
If you are interested in knowing more about how your favorite site stands against others. Then you have to try Quarkbase. From that you can get niformation on how much traffic they’re getting, how socially popular they are, and what the most popular pages within it are. The site takes information from other sites, like Alexa, to present people with the information they’re looking for.
The ability to see how many people made the site their favorite on Digg or Del.iciou.us allows to measure how popular a site is. The more popular a site is, the information on it is updated more often. Over all, if you need to know more about your site, you should check out Quarkbase.com.
Hi! I’ve found another site valuation tool and it seems to provide competitive analysis for free. I’m talking about http://www.estimix.com .The estimation provided by estimix is the result of a complex analysis based on factors like: the age of the website, the demographic structure of the traffic, the countries where the website is popular and sources of the traffic.