For a while we have been seeing domination in certain SERPS from a single domain. Searchengineland wrote about this problem last month. In their example a single domain was dominating the SERP for “christopher jagmin plates”. It had been bugging me because a single domain can’t the 10 most relevant results for a single query in my mind.
On Friday Matt Cutts tweeted that there was a small algo change last week that will improve the diversity of search results in terms of different domains returned. This seems to have fixed the US SERPS but is it yet to roll out to the UK from what I can see thus far.