About a month ago Google made a search results interface change (highlighted on Search Engine Watch) to incorporate new text fields to search Google Base directly from the normal Google search results. The text field appear on certain search types like “cars for sale” as shown below. Today Google has made reference to this and other search interface changes on the Google blog - declaring them "only a test."
While it is "only a test" it could be a significant change since it could make it more important than ever to be listed in Google Base so that you can show up in the result set from the new search widget. If your business or web site is not listed in Google Base you might lose out on Google search traffic. I’ll be interested to see what Google concludes from its "test."