BrainAround - Q&A site for college textbook problems & solutions
Newsletter Operating System - All-in-one dashboard to launch & grow your newsletter
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
Letterfuel - Grow your audience with a curated newsletter
Spires - Connect w/ Oxford or Cambridge University tutors online
Newsletter Resources Kit - A resources kit to launch, grow, & monetize your newsletter