After reading what various SEO experts are saying on the subject, I think PR agencies should be giving a big hand to Google for its latest algorithm update – because it creates more demand for PR services. 
The update – variously called the Farmer and the Panda update – is part of Google’s drive to clean up search results by reducing the search visibility of sites with low quality and duplicate content. It is mainly understood to be targeted at content farm sites which churn out masses of low level content in a bid to achieve high search rankings (and then to sell ads). Links from article and directory sites – which are often used in Search Engine Optimisation (SEO) strategies – are also expected to carry less value.
It seems to me that by penalising less valuable content and low level link-building sites, Google is by inference rewarding those sites that generate good, useful content and have links from credible, trustworthy sources. This is good news for PRs whose skills are enshrined in helping clients produce high quality, original content (blogs, articles, case studies, e-zines, white papers etc) and generating media coverage (which can include backlinks from high ranking news publications).
Image attribution: frozenchipmunk