Badoo provides a very gaming-like experience and I believe some people just love to have fun and get matches all day long. But that become boring without further goals.
I think almost every product could get some benefits from the gamification. It’s not about fun itself, it’s about setting the goal and helping track the progress of getting it. In other words: badges, levelling up, ratings won’t fit in any product (it definitely fits Badoo) but the core idea will. If you look around you will see a lot of examples.
When I wrote that article I used a TK feature. It helps keep in mind parts that needed to be polished, but also shows how close I’m to the final result. Medium could easily add a progress bar indicating how many TKs I added and how many left. Right now it shows the number of TKs left, but it doesn’t give you a sense overall progress and immediate feedback as it’s hidden.