While tweetCC is not affiliated with Creative Commons, they have taken a keen interest in what we are doing. They have suggested that the CC Zero Waiver may be a better alternative if you want to waive all rights to your tweets.
Using the CC Zero Waiver you can waive all copyrights and related or neighboring rights that you have over your work, such as your moral rights (to the extent waivable), your publicity or privacy rights, rights you have protecting against unfair competition, and database rights and rights protecting the extraction, dissemination and reuse of data. (Source)
The CC Zero Waiver gives people who want to give up copyright protection rights a way to do so. Once you or a subsequent owner of your work applies the CC Zero Waiver to a work, the work is no longer yours in any meaningful legal sense. Anyone can then use your work in any way and for any purpose, including commercial purposes, subject to rights others may have in the work or how the work is used. Think of the CC Zero Waiver as the no rights reserved option.
PDDC was intended to allow copyright holders to dedicate a work to the public domain, and to allow people to certify a work as being in the public domain. Combining these two aspects can sometimes be confusing. PDDC is also based on USA law and it may not be enforcable in other parts of the world. The CC Zero Waiver was designed to be used by anyone, world-wide.
Anyone who owns copyright and neighboring and related rights of a work can use the CC Zero Waiver to give up those rights. But please be careful. Once you apply the CC Zero Waiver to your tweets you can't change your mind later and re-assert copyrights.
You can find out more at Creative Commons CC Zero FAQ.
If you would like to waive copyright on your tweets, send a message to tweetCC via Twitter including the words
Once again, please be careful. Unlike other forms of CC licenses, once you apply the CC Zero Waiver to your tweets you can't change your mind.