Keep in touch with my coursemates
Prepare for a friend's birthday party
Organize a local community volunteering event
Prepare for exams with my study group
Plan the meetings of our book club
Move to a new place
Arrange a weekly barbecue
Stay in touch with a group of friends
Collaborate on an open-source project
Keep a private life log
Run an online community
Share favorite recipes with friends
Start a music band
...and much more!