New pay-per-click advertisements placed through Google's Adwords ad management system can now only be rotated for a maximum period of 30 days.
But the change has prompted such strong resistance from pay-per-click advertising experts that an online petition has been set up calling on Google to abandon it.
In its Inside Adwords blog, Google says it has made the change “to provide users with the most relevant ad experience”.
But even by Google's own admission, click-through rates and conversions could suffer, as ads with lower click-through rates will appear more regularly.
After the 30-day period is over, ads will be set to rotate so that those which receive more clicks are shown more frequently than any others.
The online petition alleges that the decision is short-sighted, and says: “Adwords does not care if 30 days is enough time to effectively run an ad test.
“Google is taking more and more steps to limit advertisers' [ability] to run their campaigns as they see fit and in the best interest of their individual business.”
The petition is available at www.change.org.