It hardly seems worth it, since doing so would likely require trading with strangers or giving money to strangers; one is irritating and the other is insane. Meanwhile, it seems the only material reward for obtaining a full set of cards is the possibility of a coupon alongside a bunch of virtual things that are no more useful to me than the virtual cards used to pay for them. On the other hand, all of these virtual things are worth something to someone, so more substantial material rewards — monetary rewards, in fact — might be within reach if you know how to work the system for a profit.
How It Works
For those of you not in-the-know, the newly introduced Steam trading cards are the latest in a series of secondary features added to the already-bloated Steam Community over the past year or two. (Steam Market? Steam Workshop? Greenlight? What are these "Community Hub" things and why do these discussions need to be separate from the existing Steam forums? I think I've had enough.) Unfortunately, these trading cards don't do much, and they're not part of a collectible card game like Magic: The Gathering. They're just collectibles. You can exchange a set of them to get a handful of virtual prizes, but in the end it all boils down to more collectible stuff in your inventory, more cosmetic features on your profile, and perhaps a bigger ego if you're actually proud of this.
Your first few trading cards can be earned by playing any the applicable games, and additional cards can then be received from three-card booster packs which are given out at random. However, booster packs don't seem plentiful — at least, not at this time — so getting a complete set of cards before the heat death of the universe will likely require trade of some kind.
For most games, the initial gameplay-induced card drops are based on playtime only, so you don't have to do anything in-game to get them. In fact, you don't even have to play; you can just get your cards by idling at the main menu of each game. (If I remember correctly, it only takes a couple of hours to get your maximum share of trading cards from any given game, much less than the length of a typical playthrough, so whether you're playing the game or leaving it paused for card-mining, there's no grinding involved here.) The only games with special card-dropping rules are the so-called "free-to-play" Team Fortress 2 and Dota 2, which only drop one card per $9 spent on in-game items.
Leveling Up
So what's the point of all this?
Here's a hint: Money. But I'll get into that shortly. First and foremost, these trading cards give you another reason to care about your Steam Level, an arbitrary indicator of coolness according to Valve, which appears on your Steam profile. A user's level is based on experience points which are in turn earned primarily by accumulating badges. What are badges? Well, actually, those are nothing new.
Most of the badges on my own profile are from participation in Steam's sale-related events from previous years. (Valve has a history of using the Steam community as a platform for meta-games aimed at getting its members more involved and excited about spending money, and sometimes this involves handing out specially themed achievements for the various games on sale during an event. These achievements often translate to badges and thus to experience.) Badges and experience points can also be earned for being a long-time member, participating in beta tests, and — predictably — owning lots and lots of Steam games.
The trading card thing factors into all of this because each complete set of cards associated with a given game — all eight of the Half-Life 2 cards, for example — can be exchanged for a badge. (The same badge can then be "leveled up" multiple times by collecting the same set of cards again and again.) Along with each badge comes the aforementioned handful of virtual goodies, which may or may not include a coupon, as well as a bunch of experience which raises your Steam Level. Having a higher level then increases your chance of randomly getting a booster pack of three cards.
At this early date, however, it's not exactly clear how frequently one might expect to receive a booster pack. As I mentioned above, it seems pretty rare. The trading card FAQ only shows the percentages of increased drop rates associated with each leveling milestone, and indicates that booster packs are "granted randomly to eligible users as more badges are crafted by members of the community." Without more information, I'll just have to wait and see how long it takes me to get a booster pack, if I ever get one. Frankly, however, I'm more interested in how Valve is controlling the number of cards in circulation.
Artificial Scarcity
Logging playtime will only get you half the set of cards for any given game — for example, four of the eight Half-Life 2 cards — and that might include duplicates. In the absence of booster packs, a player who doesn't trade will literally never earn a badge, and a player who only trades card-for-card will literally never be able to craft badges for all of his or her applicable games. In such a system, allowing cards to be permanently consumed in the badge crafting process would very quickly lead to a shortage. Booster packs fix this, but giving them out willy nilly would lead to an ever-increasing surplus. I can only assume that the cards being exchanged for badges are the very same cards being redistributed in booster packs. After all, that would make loads of sense, especially if we're supposed to pretend that these imaginary cards are to be treated as actual collectible objects like Magic cards or vintage stamps. If it is the case, however, the seemingly miniscule odds of receiving a booster pack would suggest that a relatively small number of users are actually crafting badges.
In any case, while a user who doesn't trade still does theoretically have a chance of eventually crafting a badge, the system heavily encourages trading, which is far more convenient. The only question is whether you're trading cards for cards, or paying cash. Even more convenient than finding a stranger who has what you need, and needs what you have, is looking up exactly what you need on the Steam Market and buying it. Sounds crazy? It's already happening. Thousands of cards are showing up on the Steam Market, with the rare foil cards going for a few dollars and regular cards ranging from around 40 cents to just above a dollar. This doesn't necessarily mean that just as many thousands of cards are successfully being sold, but the list of recently sold items on the market's main page does show a few cards every time I reload it.
This brings me to Valve's other motivation for getting into the virtual trading card business. Simply put, the whole thing is designed to suck more money from the wallets of those who are prone to trading card addiction. Some people, like me, are driven to obsessive completionism in video games; for other people, that completionism extends outside of video games to stuff like this. There are people out there who will not feel complete until they've collected every card. It's not inconceivable that some poor soul might actually buy one of these trading-card-enabled games on Steam for the sole purpose of getting more cards to trade. For the slightly less insane (but equally addicted) collector, the Steam Market is there with individual cards for sale, always waiting, tempting you with an easy path to your next badge.
Free Money (But Not Just For You)
For everything sold on the market, Valve takes a small transaction fee, so even though they aren't selling cards directly to users, they're still making money. In addition to these user-to-user card sales, the introduction of this trading card meta-game brings a mess of other items to the market as well, namely the emoticons and profile backgrounds that are earned with the creation of each badge. As long as the market is alive, Valve is making money just by keeping the servers turned on.
Evil, huh? But none of this is particularly bad for the user. Sellers on the market can make some extra change to put toward their next game (if they don't want their cards and don't mind viciously undercutting thousands upon thousands of other sellers), and buyers needn't worry much about the transaction fee unless they plan on turning around selling the very same items they just bought (which appears to be a losing proposition when each buyer pays more than each seller earns). Some have allegedly made a significant profit (in Steam Wallet credit) by purchasing cards and selling whatever rare items come out of badge crafting, but I can only assume this requires some cleverness and some luck. Trading card hustling and associated caveats aside, though, it's pretty nice to have an official means of selling items that you don't want to keep, even if your Steam wallet will only grow by a few cents.
So it's not all bad, but don't think Valve is doing us any favors; if you try to look at this from the developer's point of view, all of our usernames turn into dollar signs as usual. If you think you're going to get rich by selling all your cards, think again. Valve, on the other hand, has created yet another way to generate revenue by doing very little work. They've created their own little economy in which everything is heavily taxed but nobody really cares.
In other Steam-related news, this year's summer sale is due to start pretty soon. No one ever seems to know the exact starting date, but last year's summer sale started in mid-July, and in the previous year it started at the end of June and overlapped with the July 4th holiday. I probably already own most of the Steam games I'd be willing to buy this summer, and my backlog is already long enough thanks to the incessant Humble Bundle events, but I look forward to another Steam event nonetheless. (Maybe I'll get another badge.)