The rumor "some off-site groups are seeking a private forum together with the moderators here in order to make policy for MO" is incorrect, in fact way off the mark. There aren't off-site groups knocking on the moderators' door, much less seeking to help set policy for MO. That sounds like the bubblings of some conspiracy theory.
I will attempt to clarify what is really going on, before more such "telephone" rumors emerge.
There is widespread perception within the mathematics community at large that MO is important but can be a highly unwelcoming place. You may disagree with that, but the perception is undeniably there. And of course the members of the MathOverflow board are highly aware of that perception, and that it may be a serious problem for us in the long run. What should or can we do about it, if anything? We really don't know. Should we simply close our eyes to it, pretend there's nothing there? Doesn't seem like a good idea.
After some internal discussion within the board (which consists of the current moderators, Anton Geraschenko, and Ravi Vakil who has been part of the MO venture since the very beginning), we've put together a list of people who we thought might be able to help clarify the nature of the perceived problem. The list comprises both MO community members of long standing and respect (both here and IRL), as well as others outside who are prominent in the mathematical community, and who see MO from the outside. It's we, the board, who are seeking them out -- not the other way around. Only a few so far have gotten back to us. And they are not 'groups'. They are disparate individuals that some of us know, who have their own ideas and opinions, and who will probably disagree with each other in various respects. They didn't even know this was coming. But they are on the list because at least some of us know them, and trust to be people who can help drive a fruitful conversation.
And for now we are simply proposing to have a discussion (none has occurred yet), and yes, if we reach some shared idea about what the problem is or how extensive it is, we would also encourage suggestions for what (if anything) might reasonably be done about it. This is not even remotely close to the point of "setting policy"! For example, there would be no 'vote' taken within that group. We would not propose or presume any policy-making without an open discussion, here, before the community.
The list of people we compiled is not a matter for the MO Community to vote on, nor is it even a matter up for discussion. It is not after all a deliberative body that will vote to make decisions for the MO community and for which minutes will be taken and made public. Additionally, I hope it makes sense that sometimes, in order to have a frank and productive conversation where people can freely speak their minds, it's not always a great idea to have everything be public. In the present case, we feel discussion will flow more freely if the participants know that their speech will not be dissected in a public arena so that every word must be carefully weighed and measured.