I have been using Microsoft List Builder previously. You product is excellent. I will be cancelling my List Builder at the end of this month!
I think this is an excellent way to acquire paying customers AND will give many potential users the option to see if they can build a decent subscribership without having to front the $250 or more that would be needed for ListBuilder.
I've been a long time subscriber to your ezine mailing service (many years now) and absolutely love it!!!