SpyFu
http://www.spyfu.com

Spying on your competitors isn't new. It's the actionable take-aways that set SpyFu apart. We reveal the keywords your competitors are buying and which ones they optimize their site for. Once you find their trusted advertising secrets, you have a map to high-performing keywords, ad copy, and content ideas that create successful search marketing campaigns. Search SpyFu for domain ad copy, keyword popularity, and how sites use SEO to snag the greatest share of traffic. From Top 100 Ad Buyers in your city to the biggest CPC terms in your niche, SpyFu reveals information that builds your business.