Here is what I understand from this discussion:
1. Those living in USA or in any country that does not have Islamic Government are not subject to any Zakat.
2. Each of us is required to donate whatever surplus he/she has. Since there is no Islamic Authority to decide what is the "surplus" for each of us, each of us should honestly decide what is "surplus" that has to be given away for welfare of the others.
If my understanding is correct, I have some questions which would apply to those living in real world of today.
1. While trying to come up with "surplus", should I consider my children future educational needs, my retirement age needs, my needs if I lost my job, etc. etc. and save for these, or take my monthly surplus, if any, and donate it?
2. It seems to me that if a person donated like this, there would be no question of leaving any inheritance.
3. What should a person do who has a business that employees quite a few people, he makes good profit and would like to invest in his business to expand it? What would be surplus for him?