I've noticed that July 26th (my birthday) is used really often in various PHP examples related to preventing http caching using Expires header, like:https://stackoverflow.com/questions/12398714/cache-issue-with-private-networking-streamhttps://stackoverflow.com/questions/2833305/how-to-expire-page-in-php-when-user-logouthttp://expressionengine.com/archived_forums/viewthread/81945/What's special in that date?
What's special in July 26th and why is it used in examples for Expires header so often?
php;headers
Probably somebody did that as an example of a cache expires a long time ago and then everybody copied it.  Interestingly it's often expressed as Mon, 26 July 1997, but the actual date occurred on a Saturday.  It's not that interesting in terms of UTC seconds (seconds since 1970) since it is 869893200. Maybe it's just an example of CTRL-C/CTRL-V coding?