Google AdWords is now testing a new ad extension, which is similar to call ad buttons, for sending SMS or text messages to the advertiser.
Check out the following screen shot showing the message icon in the AdWords ad unit:
Search Engine Land tried reaching out to Google for more information, and came back with this statement:
We’re always experimenting with new ways to connect our advertisers to customers but don’t have further details to share at this time.
This information had been received by an anonymous tip from a reader.