Ordinn replied a thread concerning the Meeting Stones new feature to be included in the next content patch:

I have one quest left in RFD, and it’s a huge pain to get anyone to go there. So… do I go to the stone and add my name? Then go off and quest on the other side of the world where my other quests are? Do I wait? Are people ported to me?

No one is “ported.” You click on the meeting stone and it will automatically try to place you in a group. If there are no groups immediately available you can go quest to your hearts content. As soon as a group is available it will add you, and at that point you will have to travel back to the instance.

Does the meeting stone scan the “LFG” channel for the keywords or quests pertaining to that instance? Does the stone respond to people saying “LFG RFD” in Ogrimmar? If I’m next to RFD do I get an update in chat?

No. Players have to click on the meeting stone in order to be placed in a group. As for an update – you will automatically get placed in a group if one becomes available