In various places in OS X and macOS you see the option of sharing things to friends and contacts from a little Share button that looks like an arrow going up out of a box.
The best bit, though, is that Macs keep track of how and to whom you most often share stuff.
So, if you're in the habit of sharing funny links with a friend and AirDropping files to a colleague sitting next to you, these options will get stuck to the bottom of the share menu to make it easy to pick those options next time.
So, if you're in the habit of sharing funny links with a friend and AirDropping files to a colleague sitting next to you, these options will get stuck to the bottom of the share menu to make it easy to pick those options next time.