It's an interesting post. Each country has special rules about how the user's email address is used. In Netherlands for example you can't use a shopper's email address to send them advertisements and offers unless they explicitly approve so.
yeah if there was a checkbox right under the email field that said "remind me" or something like that, it would be OK. It's kinda scary that a few keystrokes are aggressively saved for advertisement purpose.
Yeah, and many other companies. See: http://customer.io/ (funny how that is included in the poster's screenshot).
Most TOS state something to the effect of any data the visitor enters, types, or submits is fair game.
I don't think there is anything wrong with this approach and will likely use this type of solution to aid in conversions on my sites. With 40+ percent of users exiting half-way through a form I think this is good business. So long as the initial email includes an unsubscribe.