One side of their approach is, of course, the mighty banhammer. They hand out account bans for ISK spammers, macro users, and players who attempt to sell ISK for real world cash, although ISK buyers typically aren't banned. ISK buyers may log in to find they've been caught and a GM removed that purchased ISK, giving the player a negative wallet balance.
[Some feel this is too lenient, but that negative 1 billion ISK (or more) hole in a player's wallet is probably a bit more than a slap on the wrist. Perhaps the problem is so widespread that banning ISK buyers as they do sellers would affect the company's bottom line? In any case, as it stands now, ISK buyers don't receive account bans for this activity.]
The other half of the CCP Games offensive against RMT is the 30 Day Pilot License Extension, typically referred to as "PLEX."
A PLEX is essentially an in-game item that represents 30 days of game time. They can be traded or given to other players, bought and resold. Once an EVE Online player has a PLEX in his or her possession, all they need to do is right click and credit those 30 days to their account.
The principle behind this is what's already been established by some of the free-to-play games on the market. Those with disposable cash in real life but who are short on time can buy game time codes and convert them into PLEX, so they have ISK to spend in-game. (One game time code = two PLEX.) When they sell PLEX on the market in EVE, that's money that players injected into the game that didn't go into the wallets of aklfjalkfjd and his merry band of ISK farmers.
Likewise, players who have more time to rack up the ISK through gameplay can buy PLEX in-game on the market, and play for another month without having to pay a subscription fee.
The ability to convert real world money into EVE's currency, legitimately, has been a point of contention for some EVE Online players. Some have been vocal about how they feel it's a step in the wrong direction, essentially making it OK for players with disposable income to buy what they want rather than earning it through in-game methods. But the CCP Games stance on the matter is that some, or many, players will still do this whether or not CCP enabled a secure system. The advantage for players who want to lay out real cash for virtual goods in the game is that they won't expose themselves to the risks of an account hack by using the legitimate system, although they won't get as much ISK for their real world cash as what the ISK spammers promise.
On CCP's side, this means less time spent tracking down ISK buyers and investigating them, and less risks of account hacks they need to sort out. Plus -- and this is likely the main thing -- they claim a substantial revenue stream formerly dominated by shady ISK farming and selling operations.
A dev blog from EVE's GM Grimmi -- The Way of the PLEX -- explains more about how CCP has used PLEX to combat the various RMT problems in the game. Grimmi writes,"The way of the PLEX benefits everyone involved. The very serious effects of the ISK seller rabble on EVE are limited. Your money is channeled into making EVE more awesome rather than ruining it. Players can use their ISK to play the game and save up their hard-earned RL moolah... In short, everybody wins. Everybody, except the account hacking, credit card stealing and macroing ISK sellers, that is."
While that sounds reasonable, it's been hard to actually gauge just how well-received PLEX really is by the playerbase. That is, until today. GM Grimmi's dev blog charts PLEX creation and usage since they were introduced to the game, and also shows PLEX market activity for 2009.
There's been a steady increase in the adoption of PLEX by the playerbase and presumably a steady decrease in what the ISK sellers are earning, but is CCP Games winning the battle against ISK farmers? This is unclear. Still, the prices listed in the ISK spam promise more ISK per dollar than ever in the past. Factor in that these illegitimate operations are getting more aggressive with account hacks and perhaps CCP's tactics have had an impact.
GM Grimmi adds that the other half of CCP's two-prong attack on RMT (bans, item confiscation, ISK reversals) will be the focus of a dev blog next week, detailing their operation "Unholy Rage." Given the recent mass banning of spamming and macroing undesirables from EVE and that retaliation of the ISK sellers on the forums, we're looking forward to hearing more about this Unholy Rage.