I think part of it is a change in "hot" technologies.  I subscribe to a fair number of e-mail lists and I think lists for devops, cloud-computing and ruby make up for the loss seen in lists related to PHP and Linux.  I'm sure twitter and such has taken some bite out of mailing list activity, but I think we're a long ways from mailing lists going the way of the dinosaur.
-- 
Paul Mooring
Systems Engineer and Customer Advocate

www.opscode.com

From: keith smith <klsmith2020@yahoo.com>
Reply-To: Main PLUG discussion list <plug-discuss@lists.phxlinux.org>
Date: Wednesday, May 1, 2013 11:54 AM
To: Main PLUG discussion list <plug-discuss@lists.phxlinux.org>
Subject: Are Social Networking Sites Reducing Activity on This List?

Hi,

I belong to a number of tech mailing lists such as PLUG and AZPHP.  The AZPHP list has gone almost completely dark.  It has been that way for maybe 3 years??

I'm wondering if the social networking websites might be drawing down membership and activity.

Any thoughts?

------------------------
Keith Smith