It's very important to know yourself and your competitors. I am making this tool for my own usage, I guess it's also useful for you guys here. It's build with Google Apps Engine. The url is here: http://stc.appspot.com Webmasters, SEO/SEM specialists, and domain owners can compare and measure website statistics for up to 5 domains at once, switch traffic chart from Alexa, Compete, Google Trends, Quancast all in 1 page and generate report pages that are easily bookmarked and shared. A bookmarklet is provided so you can easily view any website traffic in one click! And you can config your default compare sites, so every time when you click the bookmarklet, it will compare the current site you are viewing with your pre-configured web sites. Try here: http://stc.appspot.com Please leave your feedback here, I will try to improve it based on your feedback.