All of your clients would need their own copy of Contribute, and it quite frankly sucks anyway (at least last I used it). The Mac client was very quirky, the code absolute garbage, and the headaches in trying to straighten out the goofy things people do with Contribute not worth it.
In this day and age of having a gazillion web-based content management solutions to choose from that don't require paying for a special client, that people can access from anywhere, and that generally work very well, I honestly don't see the point in using Contribute.
Just my two cents. I'm happy to provide some alternative suggestions if you need them, I'm sure many others here have ideas too.