A WebmasterWorld thread has some savvy webmasters and SEOs asking if Google has changed how they handle the domain clustering in the search results.
Domain clustering is when Google will determine if they want to show one or more search results on a single page from the same site or not. Often, Google likes to "diversify" the search results so that in many cases, Google doesn't show the same search results from one domain name.
One webmaster wrote:
Has anybody else noticed domain clustering? I keep seeing the same site listed multiple times in the top 10 search results. Two, three or four listings all for the same site.
Forum moderator, Robert, responded:
I've seen a return of domain clustering, but only for very long tail queries. It's likely either that Google is testing something new in the algorithm, or has decided to refine results on extremely rare queries. Can you characterize what you're seeing, and what type of query, without going into specifics.
Google has time and time again tweaked how they do domain clustering in the search results. So Google could have made a tweak recently.
Forum discussion at WebmasterWorld.