Are you suffering from a lower CTR recently? Have your conversion rates declined? Have your impression rates declined, or suddenly boomed? I think I know why. Here’s a simple description of the problem that Google has caused. I’ve a longer article, with more of the background.
At some point (I don’t have an exact date and I’m still digging through client logs) Google changed the basis on which adverts are shown. Until this change, Google would look at what the user typed in a search query, and deliver adverts where the advertiser had selected a keyword that matched the search query. Google has not announced that they are now doing Search History Permutation.
After the introduction of the Search History Permutation, Google takes all the words in the previous search, and all the words in the current search, and jumbles them to make new search queries.
The result is that adverts mix relevant results and bizarre conjoined researches - even if the series of searches conducted by a user are related, the result of permutation can deliver completely irrelevant adverts.
This is not AdWords, as I’ve used it from 2004 to 2007. This is a different AdWords. It is less effective. It is more expensive to use. It is less under my control - I can’t find any simple way for advertisers to prevent appearing on irrelevant search queries.


Look at these two search results clips. Both searches are for “US Vacation”. But the search before these was varied. Notice that Organic Search results are the same. Only paid search has changed - and it has changed so that the top position results are irrelevant. This decreases the CTR for what should have been the number one advert. It has pushed to lower positions, previously relevant adverts, off the first page - so for some advertisers, impression volumes will have crashed. The recruitment of irrelevant adverts means that *high bidding* adverts, will get increased impressions, as they will be dragged into irrelevant searches more frequently.
The general effect of this though, will be plummeting CTRs. It’s almost as if Google was spamming its own pages!
Summary
I believe that Google has fundamentally changed the nature of AdWords, without any contractual variation or notice. If so, this is not ethical behaviour by Google, and it might not be legal - I don’t know enough about US law to say - but it really, really sucks.
I believe that the change benefits Google - by having more high bidding advertisers in every auction.
I believe that the change does not benefit users.
Longer term, I believe that this damages the brand value of Google, by destroying the basic proposition that Google offered to search users - that Google would deliver the best page of search results. By delivering adverts from irrelevant searches, Google has reduced the value of the page, for advertisers and for users.
I have a *much* longer article, that covers all of this, in more detail. :(
