Responding to a business proposal

I get e-mails from other people, inviting me to participate in their business ventures. I respond in the following manner:

* I send an acknowledgement first. This tells the other party that I have received the proposal.

* In a few days time, I send an e-mail to ask the other party to call me at a certain time, on my telephone number. This allows the other party to tell me more about the proposal and for me to ask question.

* I will consider the matter further, and give a reply after a few more days.

This idea may be important to the other party. I like to give it some careful consideration. I may only be participating in only a small number of these proposals, but I shall try to give some thoughts to each proposal.