If the name didn’t give it away, SpyFu is a keyword research tool with a focus on analysing your competitors keywords, showing you what keywords your competitors pay for (or rank for organically), the amount of clicks they get, and how much they pay.

It also allows you to monitor your competitors for AdWords campaigns, letting you know when ad spend changes, as well as informing you of competitor’s keywords that you’re not competing on.

One wonders how they come across this data, but they come highly recommended from around the web.

Admirably, SpyFu offers a no-nonsense approach to paying for their services, with low costs and unlimited data and downloads.