The internet was recently set ablaze by a storm of complaints from Diablo III's early adopters, furious that they couldn't log into the game on launch day. Teething problems at the launch of online games should generally be expected, particularly for games as ludicrously popular as Blizzard's, but beyond the usual failure to appreciate the realities of game publishing there was a much more interesting undercurrent of ignorance. Many players are outraged that they have to connect to a server just to play their new game in singleplayer mode. Here is the thing: Diablo III is not a singleplayer game.
Diablo III is a persistant, massively-multiplayer economy with a popular solo game experience. At all times while you are playing - AT ALL TIMES - you are sacrificing some of your time and energy to generate capital within its chaotic, splintered realm. This is the foundation stone to the entire Diablo III experience; if you choose to ignore this and get mad about having to log in all the time, you are only making yourself angry.
This begs the question: Why did Blizzard make it this way? I can think of two strong reasons. Firstly, the obvious incentive of cutting down on piracy with additional DRM controls. Speaking from personal experience, I once played through Diablo II with a friend over Battle.net using a cracked copy of the game, so I can appreciate that they would want to tighten their controls this time. Secondly, the existance of the Real Money Auction House means it's more important than ever that they stabilise the secondary market by clamping down on hacked and cloned items (which is a lot easier to do when you can enforce constant server-side checks). Blizzard take a cut from every transaction made through this feature, and I suspect that this will earn them more money than sales of the game.
I recently described Diablo-style games as "a spreadsheet attached to a fruit machine". To elaborate on this, these games have a plot and frictionless multiplayer tools and seriously beautiful aesthetics, but in my experience the player's primary source of pleasure - the main driving force that occupies their mind throughout play - lies in optimising their character build (the spreadsheet). Partly this is down to skill and stat selection, but those only come into play when they level up - in Diablo III's case they can always respec, but once they settle on a build your stats are still fairly fixed. The main thing players are interested in during minute-by-minute play are the tiny, incremental stat bonuses they get from items, which are randomly generated every time they kill a monster or open a treasure chest (the fruit machine).
As an experience, I would say games like Diablo, Titan Quest, Torchlight et al are like panning for gold. I run through these environments, obliterating mobs like piñatas and sifting through their remains for money, weapons and armour. Every new item is afforded one quick glance. If it would raise my core stats or skills, I equip it; if it offers a high value/space ratio then I'll drop other items to make room for it in my inventory, and sell it to a vendor later; if it fails both these tests I won't even pick it up. These microanalyses are a constant feature during gameplay, and can take place up to 100 times per minute. As you read this, millions of hands are clicking on billions of randomly-generated items, 24 hours per day, sifting, sifting, sifting.
With this in mind, the Real Money Auction House seems like a coup for Blizzard. Every player has access to a safe and secure marketplace that has a guaranteed reach to every other player. Because players can cash out their sales, they can feel like they're earning money from playing their favourite game - a strong incentive! Meanwhile, the strongest randomly-generated items in the game will gravitate towards the players who are most willing to pay for them - a capitalist definition of efficient allocation, certainly. One sector of the playerbase will spend hundreds of hours clicking their left mouse button to generate random numbers, and another sector will buy the highest randomly-generated numbers from them, and Blizzard are sitting in the middle and taking a percentage of every transaction.
This is the massively-multiplayer aspect of Diablo III that many players seem to overlook. Times have changed since Diablo II, and regulating the market for items has become an integral part of the design. If you think that this is amounts to an evil plot to exploit the players, bear in mind that third-party item farmers and trading houses have been running similar businesses for over a decade now - all Blizzard have done is to internalise the secondary market, so at least (some fraction of) the money that people would have spent anyway will now be going to the game developers and helping to fund future expansions.
Somewhere is all of this is a story about Marxist readings of gameplay and labour. Personally I'm a bit dubious about that sort of thing, because 'labour' usually seems to be used as a stand-in term for any kind of effort whatsoever - imagine a Marxist analysis of having to walk to the fridge to get a cold drink. I just want to make it clear that, if you are angry that Diablo III requires you to log into a server just to play a singleplayer game, you have fundamentally misunderstood the product you have bought.