Just a few months ago I was desperately looking for an online video editor. My laptop was slower than molasses and I didn't have a desktop. I couldn't find anything that would fit my needs.
Since then the new cheaper Chromebooks have come out and schools have been buying them like mad. This in turn has encouraged online developers to improve their products. Or maybe the cause is different, but at any rate I found two quick and easy chrome apps to create movies.
The first was http://www.wevideo.com/ This was a bit difficult, but only I think because I was using the advanced editor instead of the simple editor.
I liked the option of adding my own voice over to the movie. I tried playing the movie and recording a voice over in audacity, but for some reason the timing ended up being wrong. Instead I used the wevideo voice over tool and it seemed to work out fine. It was nice to watch the time of the sound slowly expand so I could almost get my timings correct. (this is only a feature in the advanced editor).
See the screen cast of doing that. http://youtu.be/zb5s3KBNOg8
Finally a video I created using the tool. This first one took me a few hours because I was learning the tool, but the second one I did took just a few minutes. The biggest detraction is that it takes forever to encode the movie for viewing.
As you can see the video has a wevideo watermark and is in standard definition. It costs extra to removed those, but the cost seems very reasonable.
I also like Mozzilla popcorn maker. They make it very easy to modify and add to the video. I especially like the options of adding twitter streams and such. The only drawback to Popcorn is you have to upload the video somewhere else first, youtube, vimeo, or just your own website if you know how to present it with HTML5. I might try that sometime later.