If you have a high participation level, you are preferred and get a higher priority in a download queue.
To get a higher priority you have to let people upload, by downloading your level sinks.

Also you get a higher priority if you rate files.

This feature gives the people motivation to share and help to contribute, I think its a good idea actually.

To read more about it you might want to check out:
http://www.kazaa.com/us/products/index.htm