GoG really seems to get the digital distribution model. Impulse buys are really where the power is. Back in the late 90's I said that if DVD's cost $5 when they came out instead of around $20, I'ld likely buy 10x as many DVD's. Same with music. Essentially, Hollywood would capture 2.5x of my money at virtually no cost to themselves (I think the average DVD, packaging included, costs around $1 to make). And I think most people are the same way. In essense, they would increase their profit simply by lowering prices to where people don't even think twice about buying the item.
Well, Hollywood still hasn't caught on. The music industry has to some extent (I've never bought much music, but once I could buy drm free at Amazon for .99 per song and often $7.99-$9.99 for an entire album, I've bought a lot more).
I never played M&M, but always wanted to. I'd never pay $20 or whatever used to be charged for the retail version. Even at $9.99, I might buy it, might not. But on sale for $4.99? Done. I'll get to it when I get to it, but it's an instant buy. And I'm sure there are a lot of other people doing the same.
The only other digital distribution site I've seen that gets it is O'Reilly books. I do a lot of programming, so I buy books on a fairly regular basis. I got a Sony Reader so I don't have to have my tiny desk cluttered up. Even so, paying $39.99 or more for a technical book is an investment. I have to really need/want it to invest that, especially without a physcial copy. But O'Reilly has the 'Deal of the Day.' Books usually between $4.99 and $9.99. Now when something comes up that I am even remotely interested, it's an instant buy. Might as well ast $4.99 right? Who knows when I might get around to making an iPhone app! Or learning Python? Etc.
(Granted the past month I've noticed the prices are more in the $14.99-$19.99 range).
They also ran a deal last month that any of their print books you owned, you could get a digital copy for $4.99. I already had PDF's of most of mine that I downloaded, but they were selling the ePub ones that work much better on the Readers. I spent $50 or so that I never would have if they had wanted me to pay $10,$20 or whatever.
Anyways, bit of a tangent there, but I love that a least a few players in the market get that trying to keep prices high actually hurts total profit.