Can I create a follow-up recipient list based on who has or has not opened my email?

Yes, from the Email Delivery tab of the Overview page, you can select the appropriate piece of the pie chart. Once the grid on the right has populated, click on the Create List button directly above the grid. You can then give the new list any name that you would like. This new list will be available to you on the Contacts List and you can use it in any future campaign or survey.

You also have the option to Resend Campaignto just those who have not opened.