Gmail's text-based advertisements are so unobtrusive that they're sometimes unnoticeable, which might explain why Google is now testing display ads with color images.

Testing began a week ago, but went undetected by the tech blogosphere until Search Engine Land's Greg Sterling spotted a display ad for organic cotton T-shirts in his Gmail account. Google has since confirmed the test with the following comment:

"We're always trying out new ad formats and placements in Gmail, and we recently started experimenting with image ads on messages with heavy image content."

More: http://www.pcworld.com/article/218059/