Andrew Davis from the CPC Strategy blog informed me of a Google Merchant Center Help thread where dozens of Yahoo Store Merchants are complaining that their product images are not showing up in Google Image Search and the images are not showing up in Google Product Search and Product Ad results.
The reason appears to be because Yahoo recently decided to block Googlebot-Images from crawling the store's images. Do to this block, these merchants products won't show up in Google Image Search but more importantly is preventing the images and so other data from showing up in Google Product Search and the AdWords Product Ad results.
Andrew received a notification from Google that informed him of this, it read:
Thank you for participating in Google Product Search. It has come to our attention that a robots.txt file is preventing us from crawling some or all of the images on your site. In order for us to access and display the images you provide in your product listings, we’d like you to modify your robots.txt file to allow user-agent ‘googlebot’ to crawl your site. Failure for Google to access your images may affect the visibility of your items on Google Product Search and Product Ad results.
To ensure the 'googlebot' is not being blocked, please add the following two lines of text to the end of your robots.txt file:
For more information on robots.txt files, please visit http://www.robotstxt.org. If you have any questions, please contact your webmaster directly.
The Google Product Search Team
One person received a response from Yahoo on this where Yahoo downplayed the importance of merchants needing Google and other search engines from accessing and indexing their images. Yahoo said:
There is not any really good reason to have all of your images on Google image search. The only big reason for that is to grab images that are free and not link to your site, I can see it helping every so often but not worth the time or money at this time to go after. But that is just me. I have not seen any thing that supports merchants in Google image search.
Seriously? Yahoo! Seriously?
Forum discussion at Google Merchant Center Help.