There are many ways to get people onto your list. Lead magnets are one such resource. For example, you can build ebooks, checklists and cheat sheets. But you can also do content upgrades, such as PDF versions of an article with added resources in them, four-part video training series, and more. Think about your audience and what you can offer them to better serve them, then treat them with some respect and you'll eventually reap the rewards.
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.