Postcrossing. Once you sign up for the service, you can begin by sending 5 postcards to individuals around the world, all of whom are chosen randomly for you by the website. Each postcard has a unique number that you write on it (provided by Postcrossing) that allows the postcard to be tracked when it reaches the recipient (or if it goes astray and never gets to its destination). With each postcard that arrives safely, your name is placed in the queue to receive a postcard from someone else somewhere in the world. So if you keep up with the service, you can be constantly sending and receiving postcards. While you can't demand certain kinds of postcards from others, you can write in your profile about the kinds of postcards you like, to guide the people sending you postcards. While I am not a very faithful postcard sender, it is a fun and wonderful service. As you send more postcards, the number you can have out at any one time gradually grows.
Dover Publications in hopes that that will tide me over until I do some more traveling. I have also ordered some postcards from Zazzle that have pictures of things and places from my state. We'll see if all that will be enough!