If I'm doing a zip submit or email submit that offers a free calculator, and I go to say adwords and bid on free calculator and type get a free calculator in the title/description, that's incentivizing?
Incent- You promised a reward or money if you get your customer to do what advertiser wants. IE Incent: Zip and Email Submits is just that. You will be paid on either an Zip or Email then you split the money with the customer who clicked on it for you or you add it towards a bigger reward.
Noncent- Which is majority of the advertising out there who doesn't want you to promise an item or money to get them to check out the zip or email submit or whatever other advertising out there. So if you see zip or email submit in this category you don't post on your site if you are rewarding someone for checking that piece of advertisement out.