Zimmer Twins is a fun site for digital storytelling that looks like a cartoon. What makes ZT so great is that it can be used in education and is fairly safe. The reason I say "fairly" is because there is no true filtering going on. However, they do have strict usage policy which they enforce so nothing inappropriate gets posted (they have a flagging policy)
Zimmer Twins is a standard Web 2.0 app. A user can rate, comment, and share their videos. Creating a video is simple as ZT is a very user friendly site.
Below is my sample video (ignore the watermark)...
Give Zimmer Twins a try by clicking here.
For another excellent review and great place to find little gems like this, check out Ozge Karaoglu's wonderful blog.