I would like to recommend the following links if you also really enjoy sending/receiving postcards and leaving some sort of worldwide impact:
Postcrossing
Postcrossing is a site dedicated to those who enjoy sending and receiving postcards from around the world. You are given an address of a random individual so you can send a postcard to it, and from there someone else receives your address and sends you a card. So, there is essentially a balance between sending and receiving postcards and thus allows for a constant flow of card-sending!
Kiva
Kiva is a site where users can send loans to those across the world to help individuals start a business or service. Once these individuals have received their loans, they will start to pay them off as their businesses begin to draw consumers.
The Prince & Princess Academy
This site is dedicated to improvements in education and learning conditions for the children of Ghana. My friend is one of the creators and facilitators of the project – users may donate money or textbooks to the academy and will consequently receive gifts in return for their contributions. Gift types are displayed on the site.
Osfast
The Creator and sponsor of this website. He’s a great friend and super nice guy. Tyler will extend his gratitude some more later 😀 (Edit: well-played, Oscar… XD)