There is a feature request on the uservoice pages for the calendar synch. The more people who vote for this (and you can give up to three votes per feature) the more likely it will happen .. so please vote!
Ah I've seen your reply on there .. I notice you compared it to the guild roster import. I suspect those are very different - the guild roster is accessible and viewable by all, on the Armories. In order to see the guild calendar, you have to be logged in and a member of that guild - I therefore guess the way they would have to do it (which I believe I've seen suggested elsewhere) is have the information from the calendar copied using an in-game addon - however that would be a one way street.
I'm not sure if other sites use it .. I'll perhaps go and have a poke.
Yeah I've just had a look at Enjin and it doesn't look like they do it either. In fact I can't see anyone doing it, so it may not be possible - certainly not in the way the roster is pulled across. I think the advantage GL may have is that they already have an addon that kinda does this sort of thing for the guild bank, etc, so they may possibly by halfway there. I don't know if any other hosts use their own addons.
Is it possible for the calendar on your site to synchronize with the in-game WoW calendar?
Also, what about making posts as your battle.net profile character?
Hi, we have changed the in-game calendar sync to Under Review. We will keep the UserVoice request updated with our findings.
Done. Do other guild hosting sites support this? Such as Enjin? Seems like a pretty big feature to not offer if your competition does!
I asked someone in one of the Blizzard forums, who has an Enjin site, to ask that question, and apparently their CS said "This is indeed a feature we have on our ideas list. Unfortunately we can't give any etas." - so no, Enjin don't currently support this, and have no eta to do so.
It would be a good string to their bow if GL could get there first, even if it was just a one sided upload rather than a full sync :-)