I find the concept of imposing artificial constraints on apps/interactions fascinating. Twitter was arguably the one to popularise the idea with its 140 character limit (perhaps by accident, the limit was initially there to support SMS) and now Snapchat (ephemeral posts). Are there any other apps that play on this theme?
Makes me wonder if there are other apps out there waiting to be "constrained". Here's some dumb ideas off the top of my head. What about a social network where you can only have 10 friends? What about an email inbox where you are limited to receiving X emails/hour (perhaps senders could bid on delivery priority?). What about a HN where you are only allowed to comment once a week? What about a continuous delivery system where you are blocked from releasing after you reach a quota of defects (I heard Google uses such a quota system internally)? What about a package repository which rejects packages with over 150 lines of code or some other quality metrics?