I do have a few questions, just in random order as they pop up:
1. Some users really dislike, or can't, watch a video explanation. Have you considered adding some introductory text? You can add it on the right just below the intro video.
2. The video starts with a minute or so explaining how to use a calendar app. Honestly, I think most people know by now that things can be stretched, can be a few hours or a day, etc. Why not skip those "basics", and go straight to the more interesting bits?
3. Minor nitpick - your tagging is done using the "@" sign. Why not go with the "#" sign, like Twitter? "@" is now a pretty widely used method of specifying a person. For example, say I want to record the event "had dinner with @nitz", it shouldn't consider it a tag.
4. The first big question I had, and I think most people will have, is "Why use this? What's wrong with Google Calendar/Outlook/etc?" The first thing you want to explain, on your page, is why someone should use this instead of those other calendars. Even if your answer is only relevant to 1% of viewers, make sure they realize it.
Just some thoughts, hope they help.