Dear AdWords Advertiser,
On May 20, 2008, a checkbox will appear on your campaigns’ ‘Edit Campaign Settings’ pages giving you access to an optional beta feature called ‘automatic matching.’ The feature will be enabled by default, although it won’t begin to affect your account until June 3, 2008.
…Automatic matching shows your ads on relevant search queries not already captured by your keywords. It works by analyzing the content of the landing pages, ads, and keywords in your ad group. It then shows your ads on search queries relevant to this information.
The system will continually monitor your performance on these queries and adjust its matches accordingly. Automatic matching aims to show your ads only on queries that yield a high clickthrough rate (CTR) and a cost-per-click (CPC) comparable to or lower than your ad group’s current average CPC. This way, your ads receive additional targeted traffic at a similar cost to your current traffic.
Sounds like a great way to stop worrying whether your keyword set is getting all the traffic you could get. Also sounds like a way for Google to expand click-thrus, and therefore, revenue. A win-win, as long as it doesn’t bust the budget.
Google FAQ about automatic matching
