A WebmasterWorld reports finding that Google is showing the cache date in minutes.
Typically, Google shows a date and not a countdown in minutes as to when Googlebot last retrieved the page. Here is an example of Google showing the date and not in minutes:

The boxed in date is what I am talking about.
Here is an example that I was able to reproduce on http://66.249.89.147 showing the cache date in last minutes.

This appears to be a new way of Google displaying this information.
Forum discussion at WebmasterWorld.

Comments:
Matt Cutts
08/03/2007 05:25 am
Mmm, minty fresh. :)
Byron Rode
08/06/2007 07:16 am
This is good. Will be interesting to see how it pans out over the next few months...
Deb
08/08/2007 07:22 am
Matt told a interesting information that Google "didn’t update our index for 3-4 months or more". And now it is can update with in minute. DD
Nadja Jacobs
01/14/2008 05:56 pm
sounds great was time that they index faster.
Lucky
12/17/2009 01:34 am
why wp fast google index