Seek anywhere in the video, even if it has not been downloaded up to that position. Saves bandwidth and time, since you don't have to wait until the video has been loaded in order to skip to a certain position.
Save bandwidth. Limit download speed per connection (visitor). You can set a maximum download speed (bandwidth allowance) for each visitor, this way you will prevent high-speed connections to eat alot of bandwidth. All visitors will have an equal share of your bandwidth.
Lighttpd Streaming option is included in the AVS script for free, and requires Lighttpd Server installed and configured.