If you google "online journal", you will see a bunch of sites offer a very similar service. If the word "private" freaks you out, you will be very surprise how the other competitors are advertising their private journals ;) (totally secure, always secure and etc...) GoodnightJournal.com actually warns the people to be careful with personal data rather than just saying it's secure cause I believe nothing is 100% secure if the idea comes out of your head. (https://www.goodnightjournal.com/aboutprivacy/)