I am in the process of making an authority site. I take a look at my competitors. and my strongest competitor has an alexa rating of around 400. I search the sites name.... and what do I find... they are selling it on flippa. To sell it... they post the following info server cost. google analytics adsense earning other earnings number of people running the site total expenses gross profits and 2011,2010,2009 earnings. Just all the info that I need to get a good idea of what the sites potential can be. basically... i am getting to look at my competitors books... GOD is great.