The Google AdWords Keyword Tool has long been in the toolkit of most search engine marketers, regardless of whether they used Google AdWords. In fact, it was one of the first keyword tools available freely to webmasters in order to find keyword suggestions and build keyword list.
But users using this free tool are now seeing a notice stating that in the coming months the external Keyword Tool will no longer be available. Instead, they are steering users to their new Keyword Planner that they launched earlier this year.
The keyword planner is actually a combination of the Keyword Tool plus the Traffic Estimator, so pay per click advertisers on Google can see not only the suggested keywords but traffic estimates at the same time, along with some other relevant data Google includes.
Unfortunately, a lot of the data that we are used to seeing from the Keyword Tool hasn't been integrated into the Keyword Planner, such as the ad share statistics. Google says they are working on adding a new column to give insight into ad impression share data.