Back in 2012, Valve added the "Something Special for Someone Special" to Team Fortress 2. It was a $100 cosmetic item which allowed the owner to "propose" to another player. If the proposal was accepted, a notification would be publically broadcast to anyone currently playing Team Fortress 2.
Naturally, people immediately started taking advantage. After all, $100 to get a message out to 50,000 players seemed like a great deal.
At the time it seemed like a new ring was bought every 5 minutes. But years later, I'm left with a single question.
How many of these rings people buy?
Theoretically, it should be possible to see how many players have rings in their inventory, since items are publically searchable.