Google apparently tests capitalization variations on its AdWords ads to see how it affects click-through rates. "With these changes some AdWords advertisers may find their ads appearing with capitalization that differs from what was approved in their AdWords account," reports Pamela Parker.
In the sample pictures embedded below, some words that had their initial letter capitalized in the approved ad were shown with a lower case initial letter, but other words had the upper case initial letter intact.
Though proper nouns were kept intact with initial capitalization, other words were capitalized, as well. It's not clear what criteria might be in play.
Here's the approved AdWords ad:
Here's the how the same ad displayed in Google search results:
In a releated news, Google is reported testing a new AdWords placement at the bottom of search results pages.
Here's the screenshot of the test: