Reddit has presumably decided now is the right time to monetize the existing user base rather than continuing to focus on growth. Reddit's lifeblood is recirculating and remixing content. Given the political climate around copyright with things like Article 13 in the EU it's entirely possible Reddit will be very difficult to run in a few years. Now might be the right time to focus on revenue.
What would bigger growth/userbase/SERP for Reddit look like? That is, while keeping its spartan social network characteristics. Even with the redesign (which I’m not a huge fan of personally) and the attempt to increase visibility of user profiles, Reddit still feels more like Craigslist/USENET than Quora or Facebook.
I too would focus on getting money out if the choice is between money and more users, when you're the fourth biggest site in the US and the sixth biggest site worldwide (as of a month ago; if I remember correctly; based on Alexa stats).
