DM Osbon from Sweetflag has started an interesting experiment: he wants to see how good free trials of MMORPGs are to draw players into their virtual world. He is starting with EVE and blogging his day-by-day experience in the free trial.
Understandably he is leaving out the games he already has played a lot, he simply couldn't be objective in a free trial of them. But unfortunately that means he won't be covering WoW and LotRO, which happen to be very good and accessible in the low levels, and thus very likely to persuade people who do the free trial to eventually subscribe.
Although one could argue that an open beta has many of the features of a free trial, I'm always surprised that MMORPGs don't offer free trials right from the start, or at least starting one month after the release. If a game is really good, nothing convinces a potential buyer more than playing it for a week or two. Cynics might say that it is exactly because of this that some games don't offer free trials.