Someone said:
I think I´m being annoying, so I´ll stop with this post.
Annoying? Hardly.
Someone said:
A character created just now, earning exclusively the 50 xp/(level x month) would level about October 2006.
Only if he spends the entire time in an adventure in which nothing happens for over a year and a half. Nothing happening, but the adventure thread still tied up? After a month or two,
Judges will step in and stop the adventure if there's no hope of reviving it. In 20 months, either the character should have earned far more than 100 XP the traditional way, unless he has been inactive for most of that period, in which case he's getting no time-based XP.
Someone said:
I don´t hide that I think that´s stupidly slow. An amount of experience that makes your character reach level 5 in 2011 is so small that it´s better not to give it at all.
I don't think the time-based XP is supposed to cover this kind of situation. Rather, it's meant for situations like the following:
Two characters are created at about the same time, and both join different adventures. Wizius the wizard joins The Search for Fred's Misplaced Masterwork Meat Cleaver, and Rogo the Rogue joins The Road to Somewhere Mysterious That This Vignette Title Doesn't Want to Give Away. SFMMMC starts out slow; the characters get into combat with a bunch of orcs, and the combat isn't even completed when, a month into the adventure, the DM gives up. Real life comes calling, he decides that PbP is too boring, whatever. And doesn't even check in to tell LEW he's quitting. (Unfortunately, this has happened more than once.) Another month waiting, the players decide he isn't coming back, and post in General to get a substitute DM. After a little back and forth a volunteer steps in, finishes the combat, and contributes the storyline to justify ending the adventure. After 3 months of real time, Wizius is back in the Red Dragon with 400 XP for defeating the orcs and roleplay bonus. RSM does rather better. All the players and DM keep up daily, and are very responsible about alerting if they're going to be out of touch for a week's vacation so their characters can be NPCed. The vignette is finished in three months, and Rogo returns to the Red Dragon Inn with 1200 XP, enough for 2nd level.
Wizius' player is feeling really down about this. Three months time wasted, and nothing to show for it. Especially since he sees Rogo back again at the same time, already up a level, and feels cheated that he missed out. So, the proposal goes, let's give them each 300 XP just for being actively involved in the adventure (to the extent that the adventure was there for them) for 3 months. Now Rogo has 1500 XP and Wizius has 700 XP. Wizius didn't gain a level by this, but he's getting close, and knows that regardless of what happens, his next adventure will be enough to advance him.
This is what I was getting at earlier: it's still the earned XP that drives advancement, but time spent can contribute a little. It won't make much of a difference except when you get bogged down. Since, in the long run, everyone should get their share of reasonably fast-paced adventures, most of our XP will still be coming the old-fashioned way. To make it any other way is to substantially change the model for level advancement.