There’s no specific blog for Google’s Realtime search, so the folks in that department used their Twitter account to spread the news that Realtime has tweaked how its search results look.
The new stuff seems to be what you see in the right column. The trend graph and date options previously showed right below the search box. Below those are two features that I think are new (but don’t hold me to it): Top links and Top updates. Those appear to simply be the URLs and tweets that are most popular among Twitter users (which appears to be the only source populating Google Realtime, at least for my “vikings” example above).
Postscript, January 4, 2011: At the same time that Google announced the above, the company also began showing “Top Updates” in the right margin of Google.com searches when users click the “Latest” results filter. In other words, “Top Updates” don’t only show in the “Realtime” search results, but also in the regular search results when filtered by “latest.”