Steve Rubel has noted that Google has started adding a time-stamp to SERPs (search engine results pages):
“As of right now you can’t sort Google results by time. From the advanced search page, however, you can limit results just to those that have been indexed in the last 24-hours. You can’t get more granular – at least yet. Date-filtered advanced queries are not a new feature but I believe the time stamps are.”
He also mentions a 2009 prediction from Louis Gray that suggests the real-time web is going to be a major development this year, especially with the increased popularity of blogging and micro-blogging.
As Steve notes, this has a big impact for (online) PR and, I guess, SEO.
It also places emphasis on ‘new’ content, which in turn will surely increase the prominence of the aforementioned blogs, social networks etc.
This is surely a natural progression for Google and sees yet another move towards universal search.