Time is an important concept in pen and paper RPG’s (the good ones, anyway). It can be important to know how long you’ve been crossing that desert, or how long ago the 1-year ultimatum of surrender or die from the humanoid leader was issued. A sense of time lends credence to your world and meaning to your lore, both in your world’s recorded history used in your background, and in the ongoing chronicles of new events recorded for the benefit of the players.
However, time is also extremely inconvenient for any persistent world: players log in and out, for different lengths of time and at different intervals. Characters that are logged out are effectively in a stasis field: nothing affects them, and they have no impact on the world. As a further consequence, players who log in more than others have a significant advantage over other players directly proportionate to the amount of excess time they spend playing. Is it possible to find a way around this quandry? I believe there is, though like most things worthwhile, it requires some work.
Start with the assumption that you are going to keep track of the passage of time in your world. If you figure out that the average player will go adventuring for about 3 hours at a stretch, figure 4 real hours = 1 game day. Configure your day/night cycles and seasons to reflect this 6 to 1 ratio, and institute a calendar. Now you have a time context to work from.
If we figure that the player in question logs in for 3 hours per day, i.e. 1 day in 6, this is a pretty aggressive schedule for an adventurer. The guy heads out to do battle with the forces of evil (or opposition to his socio-economic interests) about once a week, and the rest of the time he is taking care of business in town, repairing his stuff, maybe tilting at the lists or studying in the encyclopaedia arcanum. A guy with no life who plays twice a day in 5 hour stretches is going on aggressive expeditions as his full-time job. A guy who logs in a couple times a week is more casual about active adventuring, sort of a fellow who likes to bash in a few monster skulls now and again, but enjoys town life and its security. These are decent parallels for the types of players who fill these schedules.
So what happens when they log out? It’s silly to assume they are put into stasis. If they’re taking care of odd jobs as an apprentice, working as an altar boy, farming, hunting, or just engaging in some good old manual labor, shouldn’t there be a systm that reflects this sort of off-hours activity? Implement a system where the player chooses a number of options for how he spends his off hours, and based on his location and condition at the time of logout, he does them. When he logs back in, the system begins by doing some checks for him based on the amount of time he was logged out, and maybe increasing appropriate scores. Naturally, the reward for these sorts of spare time activities should be nowhere near the reward for actual play time invested in character improvement, must be curved down the longer one is online to avoid the superman after a year of logout syndrome, and never result in monentary gain (assume all monies earned are sufficient only to pay for the character’s upkeep and any incidental training fees), but it provides some sort of compromise solution for the player who just doesn’t have all day to sit in front of his computer, playing the game nonstop, and eating up your bandwidth. This can also be seen as a sort of in-game macroing system, giving the develpment team more firm ground to stand on when they implement a no 3rd party macroing policy.
The offline hours activity system can also be used to compensate for the fact that player characters never seem to sleep. Simply calculate the amount of time the character has been logged on, divide by 3, and devote that much initial logout time to sleeping before you start doing things. Therefore, a character logged on for 4 hours real time (1 game day) would spend the first 1 hr. 20 min. resting. A character logged in for 12 hours would use the first 4 hours to logout time to sleep. This is a little unrealistic (stay awake for 3 days straight, then sleep for 1 day), but it beats requiring players to actually sleep at intervals during a marathon play session. To allow for players logging in before the sleep cycle is complete, assign a variable "Sleep" to the character, that increases the longer he plays. Offline sleep decays this value.
This can also be applied to the mundane details of life that people consider "not fun." If you want to be slightly unrealistic, you can mitigate the hassles of eating and paying taxes with an offline system. Using the sample system below, simply have the character forage more initially (or pay more for food in town, if he is not foraging) based on a "Hunger" variable, in much the same way you allow him to play catch-up with sleep. Whatever tax formula you wish to apply can also be resolved on login, the character paying a tax based on the goods in his possession over time. In order to combat the phenomenon of playrs stripping naked justbefore logging out to avoid taxes, it may be necessary to apply a "TaxBase" variable that tracks the player’s possessions at intervals while he is online, scaling up the variable based on what the character was holding at the time of tracking. Taxes are then paid on the next login, based on the TaxBase accrued while online, plus a value based on how long the player was logged out and what he owned on logout.