A few Google users have come forward with screenshots of Google’s “bucket testing” of a social search feature. Like Digg, StumbleUpon and other social search engines, it allows users to actively rate or vote on search results using small icons that appear next to results. The company has done similar tests in the past.

The data gained from this rating are then used to refine future searches for a logged-in user, or perhaps his or her friends or others who have similar search patterns. StumbleUpon, for example, uses a combination of an individual’s ratings, those of his friends, and a set of categories actively chosen in advance by the user.

Google already has quietly integrated “personal search,” which does this on a more passive basis for any user who is logged into a Google account (or gmail) while searching. A social search tool would take this a step further by adding active social engagement a la Digg, StumbleUpon, et al. The time may be right for such an evolution as social search engines are slowly growing in popularity and comfort levels among online users.

Social search could also help Google gain more data about the overall patterns in preferences for content, which aids in indexing content and serving ads in new ways. This is especially true for areas beyond text, such as images and video, which are not only more difficult to index algorithmically, but are also areas where Google has a proven interest (universal search).

It could also say something about Google’s plans for boosting the appeal and stickiness of its relatively laggard News product. Among many rumors swirling about Google acquisitions, one has emerged periodically that it has Digg in its crosshairs. This latest development could have implications for its desire to build something in-house instead (the opposite strategy it took with video). Or maybe I’m reading too much into it. An interesting concept nonetheless.

Screen shot care of TechCrunch