In a WebmasterWorld thread, an advertiser is concerned at the way Google is handling some of his AdWords keywords. It appears that Google AdWords is serving customers with a common denominator keyword even though the customer did not actually bid on that keyword alone.
The advertiser was bidding on keywords that all seemed to have one word in common (he uses a play on the keyword, "widget," as an example). That one word became a keyword that Google began serving ads for in the broad match sense. When he wrote to Google, they replied:
It is possible for two-word keywords to expand to one-word keywords if that one word is highly relevant. In my case, they said "widget" had a 4% CTR and therefor Google judged this to be highly relevant to its users. They also suggested I use the negative exact match -[widget]
The advertiser is in a bit of a dilemma. He'd have never discovered it if he didn't check his web logs. He wonders why Google reduces keywords to a single term and now is making the advertiser explicitly state that they have to find negatives for broad matches that they're not even bidding on.
If I were him, I'd be concerned too.
One user proposes the following:
1) we look for ways to expand the "broad term gone wild" then we add those keywords and negatives and remove the broad term or convert it to phrase match. using google's keyword tool is a great way to see what google is "thinking" when someone types in that broad keyword
2) we also use negatives in our other adgroups for our keyword themes to force Google to distribute our ads matched with the appropriate keywords.
But really, why should this be the responsibility of the advertiser? I'd think (and hope) that most advertisers have done pretty thorough keyword research when using phrase or exact match and would certainly not want those broad match keywords to show up in their ad campaigns. These terms are likely not going to convert for the advertisers.
Forum discussion continues at WebmasterWorld.
Previous Search Engine Roundtable coverage: Expanded Broad Match Hurting AdWords Advertisers and Protecting Yourself from AdWords Expanded Broad Match.