There a quite a few suggestions so I’m sorry if this gets long.
I think it would be really interesting to be able to have protected tweets, like someone with a private account.
Also tagging people on Instagram with the tag symbol thing (not sure what it’s called) but on the photo. And being able to tag people in Twitter photos as well.
More options for Instagram’s filters, maybe updated to include more recent filters as most of them are older.
Adding stickers/things to Twitter pictures like the Twitter app allows.
Allowing different usernames from different platforms (eg. on instagram it would say JaneDoe but on twitter it would say janedoe28 or something)
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