Private social media feed with posts only from friends
Another private feed app when Signal and WhatsApp already do this.

Clean gratitude journal with private circles, but Day One and BeReal cover this ground.
Mindfulness practitioners, families, small private groups
Day One · BeReal · Path
You write a short entry, keep it private or share it to a circle. A circle is a small private group of your own making — family, close friends, whoever you'd actually want to hear from.
It shows you the most recent post first. People in the circle can react or leave a comment. There's also a daily notification that sends you something you were grateful for in the past.
Try it out on both iOS and Android. Go to grateful.so
Another private feed app when Signal and WhatsApp already do this.
Thoughtful constraints in a crowded journaling app space with no technical differentiation.
Social rec app fighting short-form content proliferation, but lacks differentiator.
Yelp for your friends list, but breaking incumbent network effects is brutal.
Generic journaling app with server-side encryption, not end-to-end yet.
Sync YouTube viewing exists—Watch2Gether and Scener already do this.