Instagram:
Scrolling through a feed of pictures that someone else has liked.
Be able to see if a user is following you just by looking at their page.
Pause videos with a tap like Vine.
Be able to use the video filters on pictures and vice versa.
Create drafts of pictures to upload at a later time.
Be able to like comments.
Be able to re-edit the caption of a picture after you have posted it.
Get a notification when someone unfollows you.
Only allow a certain amount of hashtags per picture.
Verification for the accounts of celebrities and other important people.
Twitter:
Identifying who that mysterious subtweet is about.
Read receipts on DMs.
Get a notification when someone unfollows you.
Only allow a certain amount of hashtags per post.
Facebook:
Get a notification when someone views the first picture you were ever tagged in.
Get a notification when someone unfriends you.
Only allow genuine birthday posts to be uploaded instead of insincere ones.
Netflix:
View a list of the movies you have already watched.
Actually recommend things you might like to watch.
Watch a trailer for a movie or documentary before you actually watch it.
Specify a genre to avoid recommendations for.
iMessage:
Get a notification when your contact is shared to another person.
Get a notification when your conversation is screens hotted.
Be able to take yourself out of a group text.
Be able to highlight text and turn it all into caps and vice versa.
The following list of emojis:
Taco
Cheese
Salad
Soda
Waffle
Socks
Gym Shoe
Cowboy
Astronaut
Robot
Puking Face
Rock On Hand
Middle Finger
Fingers Crossed
Dinosaur
Lion
Firefly
Jellyfish
Goose
Shark
Skateboard
Dumbbell
Vacuum
Spoon
Any ethnic person