If esenders.info can really do that, then that's good for them and you!
The bottom line is that if you send an email to somebody that they did not expect, most likely they will hit the spam button because that's the easiest thing to do than to go through the unsubscribe offer. I'm sure you and I and everyone else does that all the times.
If esenders.info can really setup the expectations properly and give away free stuff, there is a good reason for the subscribers not to hit the spam button.
Site Pro News does that also. They deliver quality articles by email daily, but also sometimes send messages of their advertisers. Since I still want to receive their articles, and although I may not like their advertisers' messages, I don't hit the spam button.
There are other tricks to get around the spam filters, but those are only meant for the experts
