1) I would avoid the word "society" or any other resemblance to Pathfinder Society. Maybe something like "Palladium Fantasy Players' Guild" or something of the sort.
2) Stick with the PFRPG world, but perhaps make up a new city in the center of it all, something nuetral among the different kingdoms and races, with it's own government (akin to the Vatican?), where everything orginates from, would be cool.
3) Strictly fantasy. Crossovers can create an organizational nightmare and will bring the rules lawyers out of the wood work.
4) A common set of rules would be good. Personally, I'd like to stick with canon, but I know that might not be terribly popular. I'm assuming that different groups would be playing the same adventures, facing the same bosses, etc. So different rules could make it easier or more difficult for some groups to get through the adventures. I know this is somewhat inevitable simply due to different gaming styles by different GMs, but uniformity with the rules could help prevent some disagreements down the road. Anyway, if rules are all homebrewed differently, organization is kind of a moot point.
5) If it's in the official books, it's fair game. Material from The Rifter should be voted on by whatever governing body is set up to run this thing.
6) Perhaps monthly or every other month, depending on how complex we want these adventures to get. Not all groups can meet on a weekly basis. We want to give people a reasonable amount of time to get through each adventure before the next is passed down.
7) Just available to GMs and either email, or a locked GM forum, inaccessible to players.
Posted publicly.
9) The number of groups is something that could take some time, and a lot of advertising, to gauge. 4 - 6 players per group sounds good to me. There are Palladium pages on Facebook, G+, twitter accounts, podcasts, blogs and other forums that should be blitzed for a few weeks, to make sure that as many players are reached as possible. I'd be willing to help out with this.
10) Avoid established social networks. I hate facebook. Personally, I'd like to see it on Google+ but I know that a lot of people hate G+, so some other site would be good. A lot of people have moral or security concerns about signing up for one social network or another, so being required to do so will drive players away. zyanitevp's suggestion of Obsidian Portal or Realm Works would be cool but perhaps petitioning to get it it's own sub-forum here would be best. It would also be the best way of getting the attention of PB themselves and possibly getting their endorsement. Of course, you could always make pages on FB, G+ and here, but that could become a logistical nightmare.
It might also be worth while to see if PB already has something like this in mind, or would be willing to endorse whatever comes out of this. Getting the input and support of existing writers could be VERY helpful. Hell, if it gets big enough and PB supports and endorses it, we could see mention or updates make their way into The Rifter. Or nothing at all, who knows.
Also, there should also be provisions for allowing online groups to participate, if that isn't already figured in. Skype, Roll20.net, Google Hangouts, whatever. I live in an area where face to face games are impossible to put together and I think a lot of other people are in the same boat.
