Most video editors allow you to record right from the camera on your computer. You may also want to record audio over existing video.
The ability to take out unwanted segments of video is vital. In general... the shorter, the better
As with audio joining segments can be very useful.
As with photos, adding text can be vital to visual communication
Most videos benefit from background music especially when they have noisy backgrounds. NEVER use non-licensed music no matter how tempting the Happy Song may be. Always look for license free music libraries in your video app. You can use this material liberally.
Video is the most demanding of all the media, both, in terms of bandwidth needs and complex compression codec. The better sites take care of this for you so that you don't have to think.
How easy is it to include your video in other places like presentations or web sites?