Why do some sites in the google search results have a date (ie..29 Sep
2002)and other sites dont and what does it mean?
Example Search for "Microsoft"= 
Microsoft Corporation
The entry page to Microsoft's Web site. Find software, solutions,
answers,
support, and Microsoft news. Microsoft Home, All Products ... 
Description: Official homepage of Microsoft Corporation
Category: Computers > Companies > ... > Consumer Software > Microsoft
Corporation
www.microsoft.com/ - 31k - 29 Sep 2002 - Cached - Similar pages -
Stock quotes: MSFT

Hi there,

Sites without a date
====================

Ordinary websites which get visited by GoogleBot and re-indexed every
month or so

Sites with a date
=================

If Google determines that a website is being updated regularly with
new content, it will send the GoogleBot there more often. Sites that
are visited more frequently will have the date of the last time the
site was indexed beside it, as you have noticed. It usually applies to
huge sites like Microsoft, news sites, forums and weblogs.

"Google refreshes millions of web pages every day to ensure that
Google users have access to the most current information"
://www.google.com/press/pressrel/3billion.html

Search strategy:
Personal experience

Best wishes,
robertskelton-ga

Has Google ever considered using the ISO 8601 date format, all numeric
YYYY-MM-DD, like the one mentioned in RFC 3339?