Google has added a "search volume data" feature to the Keyword Tool that potential advertisers use to select keywords to bid on. The new feature gives an idea of how many people actually search on those keywords.In a post on the Google AdWords blog, Inside AdWords crewmember Trevor Claiborne wrote, "Now, when you use the Keyword Tool to search for relevant keywords to include in your keyword list, you'll be able to see the approximate number of search queries matching your keywords that were performed on Google and the search network. These approximate numbers are intended to provide better insight into keywords' monthly and average search volumes than previously provided by the tool."

The Keyword Tool already offers information on advertiser competition, search volume trends, estimated average cost per click, and estimated ad positions for keywords. Google AdWords blog