Reddit is a fantastic product— and its huge, growing popularity is a sure sign of that. But it never was built with a clear business model in mind. Their two sources of revenues are (i) ads and (ii) reddit gold.
I don't think anyone ever expected (i) to be more than just a little extra cash; and (ii), as they say, was never heavily promoted at all. So it seems like (part of) their solution today is to try to push (ii) as far as it will go. I don't believe it's going to get them very far in its current state, but it's a valid first step.
I think this highlights, once again, the need to actually build a viable business in addition to a quality product- one does not make the other, and it's hard to retrofit a business model 5 years later.
Sadly, everyone expects everything digital to be free (software, social networks, services, magazines, games, etc.), so it's an uphill battle. I think Reddit has some interesting cards in its hand though: AMAs are a growing trend, so that's something I'd try to monetize if I were them.
Regardless, I'm curious to see where Reddit will go.