Google AdWords has allowed advertisers to show sitelinks since the end of 2009. Back in April Search Engine Roundtable showed examples of ads showing up to 4 sitelinks per ad. I am now seeing some ads with 6 sitelinks. It would seem as if this is somehow connected with Google’s push to expand organic sitelinks in the SERPs.
It seems that the Google help center has recently been updated to state:
If a user search triggers your ad to run with Sitelinks, our system may include up to six of your additional links on your ad, along with the main landing page link. The higher the quality of your ad, the more likely Sitelinks may be able to run on that ad.
How many sitelinks are you seeing?