I have several blogs promoting all different products. The hardest thing I find about affiliate marketing is that once you’ve sold someone something you need to find a new product to sell them. I’ve found that promoting a subscription service where you sign up a customer is a great way to go. This way every time they renew or buy something you get paid. You only have to sell them this once.
If you have pop-ups and optins on every page, I would have to think that it would be a lot harder to convince someone to link to it. Especially since the pages where you have your optins (and probably receive the most traffic) are probably the same pages that you have your best content on as well that you'd be hoping to pitch in your outreach campaign.