Right now I think Voicethread is one good option for primary students to express themselves using digital tools. There are several reasons I like it. First is that they can combine crayon/pencil/marker drawing that are scanned onto the computer with their own voices narrating a story, poem or idea. I think it's really valuable to be able to combine the tactile with the digital, especially at younger ages. Here's a Voicethread done by first graders this year based on the book The Jigaree by Joy Crowley. Jigaree Voicethread by Mrs. Abare's Class. Also, students can comment on each others' voicethread pages bringing in the web 2.0 aspect of technology too.
I also don't think we should overlook flip cams and cameras. Kindergarteners do a unit about themselves and having them film each other with a flip cam talking about themselves and their families is a great way for them to use age appropriate technology. They can't put movies together yet but they could work the camera if it was set up on a tripod and they'll love watching the movies. I love the idea I've seen for 2nd graders to make a movie about the different properties of space (gravity, rotation, etc.) and they could certainly film that and maybe some advanced students could even put the the movie together. I was surprised to see on the Danbury site that they expect their 4th grade students to create a movie and get it ready to present. Maybe this is something we need to start early if we want our students to be ready for that stage in grade 4. Two of the 5th grade teachers at Glencliff are doing a lot with flip cams this year.
2nd graders might also be ready for Storybird although it might be a little too hard for some of them to navigate.
I've used Animoto with first graders in a non-fiction unit about space. I don't like Animoto because it requires a login which I have to enter for everyone. Also, I found the pictures for them and got each movie prepped which was a lot of work. They did the writing and the typing. Still, the results are excellent quality and they were thrilled. Here's a sample.
Other ideas I'd like to look into but which I haven't done completely yet are:
Pecha-Kucha, a site where 20 slides are shown for 20 seconds each and the presenters speaks for 20 seconds about each slide. If you had a class of 20 students it would work perfectly but I love the idea because it's so finite and I think kids could handle 20 seconds. The material on the site is not necessarily kid friendly so I'm not sure if the site would be the way to go or using the idea somewhere else would be better.
Another one is SAM - stop action movie. This is free and requires no login. If you want to use more than 50 frames in a movie you have to pay but it's $30 - really reasonable! This concept uses both a camera as well as movie editing. I need to explore it more.
Wallwisher is an online corkboard/brainstorm area that students as young as first grade could use. It's fun to watch new ideas pop up and would be a neat thing to leave up on a computer in the classroom or project for brainstorming. There's another option geared toward young children but I can't find it just now. As soon as I do I'll add the link here.
Blabberize is another very fun presentation vehicle that would require some set up for young children to use but I think they would love using it and be able to express some pretty neat ideas. They would need to have more direction than I gave my son when he did this one but I think that could work. What if the students used a picture of an endangered animal and talked about how they are endangered? What about a fairy tale unit with a knight or a princess talking about life in the castle? The possibilities are endless. There's also a commenting capability with Blabberize although I haven't tried it yet.