With Realplayer installed on your computer, you can now download any youtube video and play it back without having to go and download the video on youtube every time. Already we're seeing news reports that more and more video downloading is impacting on the future of the net:

http://news.bbc.co.uk/1/hi/technology/7370956.stm

Unless Youtube implements a similar feature to its file sharing site then this is one of the only ways to download a Youtube video.
It works by flashing up text when you move your mouse over the video asking 'Download this video?' and when you click on it Realplayer will then activate to download the same video clip you're watching so that you can view it again later on your hard drive.

This saves having to download the video clip each time you want to watch it again which is very useful and could help to reduce the load on the net if more people did so. For those who have capped download limits on their broadband connection then Realplayer is a must if you're going to use Youtube.

Realplayer Basic is free and can be downloaded at:

http://uk.real.com/video/