http://www.compete.com/ 
Paid
Features:
- The only online competitive intelligence service that combines site and search analytics.
- Insights provided are sampled from the data of more than 2 million online internet users.
- Analyzes what consumers do across the entire web, and not just within a particular site.
- Possess largest online consumer behavior data in the industry.
Inside Compete:
Site Analytics:
Provides information on site traffic history and competitive analytics for a period of 1-5 years. There is an option to compare the traffic performance for 5 competitors. It used multiple data sources, including ISP, panel and toolbar to estimate the traffic figures. It also features an comparative analysis where the fluctuation of traffic is shown for websites by month and year. A number of reports can be generated based available options like page views, unique visitors, rank, visit and more.
Search Analytics:
Use search Analytics to find keywords which are driving traffic to any domain. You can see now who you are competing with and on which specific keywords and phrases. Helps you in generating a keyword list from its data of 19 million search terms. Keywords can be found for specific category also. Get access to competitive keywords for two websites. Explore keywords like never before!
Referral Analytics:
Want to know which referral web sites are sending traffic, this is the spot you should be looking for. Find out where visitors go after they leave a website. Find the referral website share for competing websites verses yours. Understand the impact and improve your decisions in marketing strategy.
Ranked Lists:
It provides a list of the most popular web sites across the web, which are ranked by any compete metrics. You can generate the ranking list based on criteria like unique visitors, page views, visits, total time spent, monthly attention, etc.