Livestream is a web-based stream video service. I use it because it allows you to broadcast both your computer screen and camera video at the same time in a picture in picture format. You can also switch between the screen and camera during the middle of the video webcast.
When you log into a channel, you have the option to view a video live or view on-demand videos (which are previously recorded videos). Deleting an on-demand video on LiveStream is not obvious. The trick is to go to My Account> Studio> Video On-Demand when you are logged into http://www.livestream.com. From there, go to the Public Video On-demand Library on the right and click the X to delete the video.