Please don't make me type my email password in your website so that if you get hacked then you take down along with you my email and possibly most other internet services and products related to me. The dangers lurking far outweigh any benefit of at all.

You should subscribed to a compendium of newsletters that we users subscribe to and then let us choose with checkboxes, which newsletters are ours and the ones we wished to use your service. You could have a "request your newsletter here" field also on your website. That would be a sane profit making service.