Google's Realtime search service is no longer available, the "Realtime" option disappeared from Google's sidebar and google.com/realtime returns a 404 error. A Google spokesperson Gabriel Stricker shared this statement:
We've temporarily disabled google.com/realtime. We're exploring how to incorporate our recently launched Google+ project into this functionality going forward, so stay tuned.
Also, another Google feature, the Wonder Wheel feature is no longer available.
"[Google's] spokesperson said that the search tool was removed due to the 'initial stage' of the Google site redesign announced [last] week."
The Google Wonder Wheel along with a number of other search refinements were formally introduced at the 2009 Searchology event but actually became available as part of a test a couple of months earlier.
A Google Help Forums shows that at other times Wonder Wheel was inaccessible to users for various amounts of time.
It's likely that both Google Realtime and Wonder Wheel had to be redesigned, but Google didn't want to delay the launch of the new interface until they're ready. When Google Instant was launched, many of the advanced features were not available, but some of them were added after a few weeks.