"SpyFu is a competitive intelligence tool for SEO and PPC. You can type in a domain to see all of the keywords it ranks for (including the content that ranks), the ads it buys on Google, and its strongest competitors. You can also do deep keyword research. Find the domains that buy it or rank for it-- all with history to boot. With deep insights and reporting, SpyFu is a solid tool for people who are starting a campaign and those who are improving what is already in motion.