As technology progresses, we're seeing more and more tangible objects being replaced by digital alternatives. Letters have given way to e-mails, paperbacks have become e-books, and postcards have become trip photos on Facebook. The fact is, though, people still like getting stuff. Postcard on the Run builds on that idea, allowing users to create and mail their own custom physical postcards, from anywhere.

Here's how it works ...

Users snap a photo while on holiday (or at home, for that matter), then use the Postcard on the Run app to digitally transform that photo into postcard format. The actual postcard itself is printed at the company's facility, then snail-mailed to the recipient's address. If the sender doesn't know that person's address, they may be able to find it using the app's built-in Postal Gopher feature.

Along with the photo on the front, the postcards also include a printed personal message on the back. Users can additionally add a signature, a mini map showing where the photo was taken, or a QR code that directs the recipient to a posted video when scanned. There's even an option of adding one of 11 scratch-n-sniff patches, that include choices such as Suntan Lotion, Ocean Breeze and Baby Powder.

The app itself itself is free (in iOS, Android and Windows versions), with printing and postage paid via the user's credit card – as an example of the higher end of the costs, a card sent from the US to another country will set you back US$2.89.