They posted another such invite on Facebook late yesterday.
Join the Barnes & Noble beta program and get early access to our new book discovery experience. Check out what we’re cooking up and help us build something wonderful for readers.
The B&N FB post links to a form on Google Docs where you can apply to join the beta group. The form asks for basic details like your email, type of phone, and the number of books you read each year.
If you would like to become a beta tester, you should go fill out a form. B&N never invites its customers by emailing directly, and will only accept new testers through that Google form.