Maybe they do but i have never had one. I am sure it would not hurt once a month. imagine if they sent an email to everyone that purchased michaelhejja xml editor version 1 that version 2 was released today. They and the author could end up with 500 sales that week.
191,000 emails should bring in quite a few more sales.
there are coming new files every day so if you need to send a mail for every file you get a lot of mails in a week
But there is a new items feed that you can subscribe to and every author has one to