When people get intensely into a fandom, they often develop strong feelings about characters. That emotional involvement can turn into shipping: "supporting or wishing for a particular romantic relationship" between characters, according to the ultimate fandom wiki Fanlore.
This gift guide provides ideas for gifts for the shipper in your life across various fandoms. Of course, you may want to casually check who they ship before you buy anything!
Nowadays it is getting to the point where you need to be on the internet to exist. However shipping company DHL may have just found one the best ways to have their name out there. What better way to advertise then have your competition do it for you.