In the application I am developing, I'd like to refer to people who have had something shared with them (link, photo etc.) but I couldn't figure out what word or phrase to use.
Recipient: receiver: somebody or something that receives something.
In this case I would describe that person as a recipient or a receiver.
According to Oxford Dictionaries, a receiver is:
A person who gets or accepts something that has been sent or given to them.
You could also simply use a phrase "the person/people you shared with".
a person who gains or benefits in some way from something