Why not use your YouTube videos embedded in your WordPress site to build your lists?
Search for a form builder that offers a responsive YouTube video player for WordPress with an extra super power: when you click play, the video stops and a form is shown instead. Once your user has filled out the form, your YouTube video continues.
Thus, making it a great way to fill your email list. Simply create a different YouTube video for each interest group and use this feature to grow your list.