The Museum 2.0 blog has a great example of online collaboration using VoiceThread. You can view that example here. The project had more than 200 participants from 131 cities worldwide.
For those of you that are unfamiliar with VoiceThread, VoiceThread can be described as an online slide show accompanied by commentary (voice and text) from other VoiceThread users. To start a VoiceThread one person posts images and records their commentary about those images then other users can login into their accounts and share their commentary on the same images or what was said by the previous person. In short, it's like having a conversation at an art gallery, but the conversation is held and recorded online instead of in-person. When you register at VoiceThread be sure to tell them you're an educator because you will get a lot of free benefits that regular users have to pay for. Below is a short video introduction to VoiceThread.
Applications for Education
VoiceThread could be used as a great tool for students, parents, and teachers to collaborate on a local history project. Local historical societies are always looking for people willing to share information and knowledge. Creating a VoiceThread to share with a local historical society would be a great way for students to learn about their local history and perform a community service at the same time. Students and teachers could invite their parents and grandparents to share their knowledge of local history in the VoiceThread conversation.