Google now automatically personalises search results. By default; people get different search results! One aspect of the personalisation algorithms is to look at where people go online and another is to study what people do online. Google Buzz affects both those things.
A really clear example of how Google Buzz impacts SEO is how it will integrate with the real-time streams that Google now produces for trending keywords. It’s all too likely that in the future these real-time streams will link to Google Buzz pages. This is a content play from Google. Searches take searchers back to Google.
Over the past decade we have seen the ways that search engines refine information – if the 1990s was about search engines sorting our Relevancy algorithms and 2000s were about search engines sorting out Trust algorithms then the 2010s are about Authority. When faced with two equally Relevant sites; both of which are trusted by Google, which one does the search engine pick to rank? Google will pick the most authoritive site. Google Buzz helps Google determine which sites have the authority as Google Buzz gives the engine an insight into what people are talking about, which sites real people recommend to one another, which news events inspire the most interest in people, how people tend to describe things, e.t.c
In addition, it is also worth noting how heavily Google Buzz leans on geographic data. Google does alter the search results to match different locations around the world and even around the UK. Google Buzz will help them with this geographic tailoring.