The first MMO I ever played was FFXI, and being the newbie that I was, I joined with a social guild that had no hardcore aspirations. Even though this guild was social in nature, people still preferred to team up with guildmates rather than join pugs, and so I would occasionally make plans to be online at a certain time to group with guildmates for whatever particular goal we were all after (usually simple grinding).
I quickly learned, however, that just because someone says they will be online doesn’t mean that they will be. In fact, the act of making plans seemed only marginally more useful than randomly logging on and hoping there would be people available.
This was very different from my next guild experience in WoW, where I joined with a long established group of people (the group was centered on a website and collectively moved from game to game).
In this guild, when someone said they were going to be somewhere it was safe to assume that they would be there. If something unexpected came up to prevent someone’s presence, the group would be informed through one of the various communication channels the guild had available.
Given the differences in these two guilds, I believe that was the deeper level of shared experiences (i.e. the longer history) of the WoW guild that led them to be more socially (and emotionally) interconnected and accountable to each other. This is not to say that the FFXI guild did not have shared experiences, but this particular social group was very young and thus had not yet had enough time to establish strong bonds.
This is not unlike the culture of the Taipei expats that I have met. Granted, I have different expectations of different people, established over time as I get to know them; but it is often the case that if I have plans with someone, the chance of them following through is only marginally better maybe.