I am on the mailchimp free plan. One reason I think it works for them is that it's impossible to stay on the free plan if you are successful. It's nice to not h

I am on the mailchimp free plan. One reason I think it works for them is that it's impossible to stay on the free plan if you are successful. It's nice to not have to pay while I'm building my list and don't get much value out of it yet. But every day, as my list grows, I know I'm going to have to pay -- at that point it would be silly to cancel. Another reason it works for them, is that many of their customers probably start with a list -- in that case, it's not free (if you have over 500 subscribers)