DLC is a pretty big discussion now days in games and in all its forms really from micro transaction style items like boosts in MMOs, costume packs for fighting games all the way up to large chunks of content like Lair of the Shadow Broker for Mass Effect 2. Now some downloadable content has been pretty exploitative of consumers and others have been really good.
Post release content actually isn't anything new. It's new on this generation of consoles because they're actually online systems now but the concept itself has been around on PCs for quite a while. It was certainly not as big a focus for many companies as it is today but it existed mostly in two forms, free bonus content that were more or less bundled into patches. And the other was full on expansion packs that were sold at retail usually cheaper than the base game and offered a pretty large amount of content.
Expansions were really good for companies because it allowed them to use a game they had already made. It made it a lot cheaper to make than the original and you could typically put it out a year after the game had been made and make a whole bunch more money. Usually it was a year after the base game had been released and they were usually sizeable in scope, Yuri's Revenge for example added a new race, a few new units for the exiting ones, new maps and a whole new campaign filled with it's own cheese filled FMV cutscenes. So consumers never really got burned too badly with this, there were definitely instances where a game got a bad expansion but that would more often than not be because the content was bad rather than people feeling they're getting gouged. I think a lot of this was due to the fact that it was a single big thing that you're getting all at once.
Free updates were somewhat more rare, they were expensive to make for potentially no reward whatsoever. Some games could do it if they had a really strong mod scene where they would roll community favourites into packs that they would just distribute. Unreal Tournament 2004 is probably the most famous example of this being done where the free maps almost doubled the total number of maps that were in it. Note: UT2004 could also be considered a stand alone expansion for the slightly less well received UT2003.
Back to more recent history and starting with the production process and how a lot of DLC is made now days, particularly day one DLC. On large teams you generally have a bunch of your people that don't have any work to do towards the end of a game, concept people and the like. Normally they would be sent to work on whatever the next game was going to be or to do prototyping for pitches in the future. But with the advent of DLC those people can work on new post release content while the main dev team works on doing the last bits of polish on the game. After that you have the wonderfully long and painful certification process which frees up your main dev team before the game comes out to work on that DLC. The cert process for a full game is pretty long but for DLC it happens to be much shorter. I expect that this is to do with slightly more lax requirements for somethings that if it works in the full game it works in the content and just generally having less things to test by virtue of being smaller in scope. So all this combined has led to a situation where you can get a piece of DLC fully finished and certified before your full game has been certified and sent out to be produced and distributed (which for a large run of physical games is also no short process). So some parts of the DLC being on the disk like art assets for example which can be finalised well in advance becomes a lot more understandable. It seems to me that it's more an argument for the certification process to be less lengthy and obtuse but I think I'm going to lose that argument with the console makers.
I understand the argument of if it's done then why isn't it just in the game you just bought. It's a fine line here, because there has definitely been times where a game would normally be delayed a little bit to get it finished and put in there. Other times it's used as a free content pack to those people that bought the game new to discourage pre owned purchases. I'm generally of the opinion on day one DLC is that it should be free, good will is generally worth more than the sales you can pick up. It puts people in a slightly better mood when it comes to other stuff you release. There have also been times where the content is just done and it's being arbitrarily held back for marketing tie in stuff or whatever and that really isn't okay. The biggest example I can think of is Marvel VS Capcom 3 where they tried to tie in bonus characters to the Vita version of the game. Which was really dumb because it meant that hackers could get into the game and play with those characters. While obviously ridiculous for that reason in competitive games you need the data to play with other people that do have paid for the new characters.
The obvious solution to me would be to be push out a large update to everyone with the new content and you're done. Again the console ecosystem comes into play where there are both maximum caps on the size of patches and also that it costs money to put out a new patch for your game, a story that was made very public by Fez. So while a sound idea not one that developers can actually do. Capcom's alternative of just putting it on the disk is actually one of the only ways you can get it to work right or you have to just have the Mortal Kombat situation of if you didn't have the DLC you just couldn't play with those people that did have it.
I suppose the last thing on the list to talk about is pricing. This is the part that is really rubbing people the wrong way, that and micro transactions. I think the main problem I have with things like weapon packs and costume packs which are glorified pallet swaps, is that they are utterly pointless. I'm sure people get some value out of them but the thing is they A. aren't difficult to make and develop and B. generally don't add too much to the game if it's being added after the fact. Now the counter to that would be they are relatively inexpensive but it feels like it's just being made for the purposes of gouging a little bit more out of people.
One of the other practices that is becoming more common in the industry is that of a Season pass for games. Off the top of my head there are only a couple games where this actually makes any sense what so ever. The Walking Dead. It's an episodic game, you're buying the whole season. Actually a lot of the Telltale stuff works here but that's kind of their thing. LA Noire also kind of fits the bill to a lesser extent because the structure of the game was very much split into distinct episodes or cases. But there have been plenty of times where people have gotten burned on bad season passes where the DLC that came out for the game just ended up bad. Saints Row 3 is a prime example of where it was a fantastic game but everything they released after it was kind of terrible. Uncharted 3 is also another example of people getting seriously burned on just not getting what they paid for.
This is a very much the same problem that pre-orders have of you're paying money for a game that isn't out yet and may in fact turn out to be terrible. The biggest distinction is that with pre-orders you generally know a little bit about the game that you're pre-ordering with wonderful games press doing previews and the like, but usually the season pass is sold when the game is released when no one has really not seen anything of what the DLC is going to be. This is kind of the worst kind of blind purchasing of 'trust us it's going to be great' that companies seem to be doing more often which is kind of not good. But people seem to be buying it which means it works I guess.
Micro transactions are also becoming more prevalent also scarily in more games that aren't free to play. Mass Effect 3 did it recently in it's multiplayer mode, which was actually more fun than most people were expecting, but it had it's booster pack system to unlock new classes and items. Now a lot of free to play games are glorified skinner box machines (if you don't know what it is look it up and operant conditioning, basically compelling people into certain behaviour) and it's that reward loop that keeps people playing and they pay money in order to keep those rewards coming even if it is something abstract like gaining levels. It feels a lot worse when put into what is seemingly a fairly core component of a multiplayer mode that is part of a full priced game. As for free to play games I think it's a little bit more mixed.
There are definitely games that do it well and there are games that do it badly. Lots more examples of ones that do it badly. But a lot of the ones that do it well happen to be MMOs, Lord of the Rings Online converted very well to the free to play model where they were very easily avoidable and they are really focussed on convenience. Tribes Ascend is an example of it being done alright where you can pay to unlock new classes and weapons but for the most part it's very balanced and paying money only really gives you more choices. The progression gain is a little bit too slow if you're trying to not spend money, but that's almost par for the course with the genre.
I've gone on for quite a bit more than I had intended to and I could probably say a lot more on the subject matter but the short thing is that DLC can be done really well. There have been lots of examples of content packs that are sizeable, well priced add ons to great games. And there are a whole lot that are really awful anti consumer gouging. The practice of making DLC and post release content isn't inherently bad or awful, some companies are trying their hardest to make it seem that way unfortunately.