Last week I covered the news that Google was letting a single domain dominate the search results for some particular queries. So when you searched for something, sometimes, 80% or more of the search results Google provided would be from the same web site.
I thought this was a bug, I mean - seriously, how is that useful? But I was wrong. According to Google, this is not a bug but rather a feature, a feature they think is useful. I don't see how it is useful to get 80% or more of the search results for a single query from the same domain, no matter what the search query is. But heck, they know search, I just write about it.
Today we've launched a change to our ranking algorithm that will make it much easier for users to find a large number of results from a single site. For queries that indicate a strong user interest in a particular domain, like [exhibitions at amnh], we'll now show more results from the relevant site:
Prior to today's change, only two results from www.amnh.org would have appeared for this query. Now, we determine that the user is likely interested in the Museum of Natural History's website, so seven results from the amnh.org domain appear. Since the user is looking for exhibitions at the museum, it's far more likely that they'll find what they're looking for, faster. The last few results for this query are from other sites, preserving some diversity in the results.
As you can imagine, there is a ton of discussion on this topic in the SEO/webmaster forums.