From the Packt Publishing web site (http://www.packtpub.com/award/):
The Packt Open Source Content Management System Award is designed to encourage, support, recognize and reward an Open Source Content Management System (CMS) that has been selected by a panel of judges and visitors to www.PacktPub.com.
If you're a fan of a particular CMS or if you're part of a CMS project team, then we're looking for your nominations. We want to compile a list of open source Content Management Systems that will be put forward to win $5,000 and the title of Packt Open Source CMS, 2006. The five CMS's that receive the most nominations will go forward to the final round. First runner-up and second runner-up will not go away empty handed, taking away $3,000 and $2,000 respectively.
Make your nomination here: www.PacktPub.com/nominations
Award Timeline: www.PacktPub.com/award_timeline
Go to the site and nominate Plone!