Penzu

With over 2MM registered users, Penzu is the most popular web and mobile app for keeping a personal journal. Focused on privacy, ease of use, and customization, the cross-platform journaling experience is truly unparalleled. 

While it's entirely free to keep a journal, Penzu has been a profitable business since inception. Penzu Pro offers premium features such as military-grade encryption, tagging, custom fonts, and smart search. 

In a world of over-sharing, Penzu will become increasingly important—expressive writing is timeless.