Thanks for the advice. Actually I have done other facebook apps that I thought are useful. But I realize that people on facebook aren't looking for serious things at all. They are generous on throwing cakes to each other, but not for any real interaction that you would do real life.

I would give it a thought since it won't be too difficult to do it in facebook.

regarding the response, yes you do have a unique URL that you can share with others. I have only make email works since it is out of my scope (my habit) to communicate with others via other channels.

again. Thanks!