Jaycut used to be my go-to tool for online video editing. It was WONDERFUL as an excuse-breaker for students when editing their video. No more "we can't get together" problems. But then it closed down.
Well, guess what? Jaycut's back, and better than ever with a sleek new design. The account is free, and once you've uploaded the video, allows simple editing. You can cut clips, add titles, transitions and audio with multiple tracks. It allows publishing either online or as a desktop download.
Here's a sample video I put together using their preset videos/audio, with a simple title in front and a dissolve about halfway through.