The Plone Foundation received its response from the IRS: it is now a tax exempt organization classified as a public charity for a 5 year ruling period.
Thanks to the efforts of Geoff Davis and Toby Roberts from the Plone Foundation, and primarily the work of Karen Sandler at the "Software Freedom Law Center":http://www.softwarefreedom.org, we were notified amazingly quickly. (Thanks especially to Karen for the patience.)
Massive kudos to the SFLC. Working with Dan Ravicher, Karen, and Eben Moglen has been a wonderful experience — thanks!
So this year, you can donate money to the Plone Foundation **and** get a tax write-off. We will be adding links to online donation forms over the next couple of days.