Gnutella only works and grows when people get =and= share. That's pretty obvious by now. Here's a few of my ideas to keep things balanced:

* Implement a rating system which allows the exchange of host ratings peer-to-peer; for example, if host 'A' shares a file with host 'B', host 'B' could broadcast a positive rating across the network which includes the file size, download time, etc.; ratings would be kept on individual hosts and shared via the network.

* Force sharing of download folders (like Xolox does).

* Implement a "allow freeloaders rarely/often/always" feature like LimeWire has.

* Display pop-up notices encouraging users to share if they're not.