Anytime a teacher wants to use Twitter, Voicethread, whatever the tool, bring them in (if you can), record a video, communicate somehow, the answers to these 3 questions:
What are you using? Again, it sounds simple but you've got to communicate what tool you are using. How it works. Are the parents going to have access to the student work? What will they be able to see? This is all the technical stuff. The depth to which you go is up to you. If you can bring them, take the time to teach them how to use the program.
Why are you using it? You've got to communicate to the parents the purpose of the use of the tool. How does it fit with the content? Explaining why you are going to use it will help you determine for yourself, the best pedagogy for the technology and how it will fit into your teaching. That, in turn, helps the parents to understand the same.
How does the use of this tool enhance student learning? The most important question to answer. How will the use of this ultimately make learning better. Why will the use of this tool be good for kids?
You've got to build those bridges with parents. The easiest way is to bring them in and tell them whats going on. Better yet, let the kids teach their parents.