Notes
Forever: Kotaku reports 'Meeting Stones still exist at the front of dungeons, but they don't let you summon other players.' Warcraft Tavern: the LFG UI 'does not form them automatically or teleport everyone to the dungeon'. Classic 1.x stones were an auto-group queue; summoning via stones came in 2.0.1 (warcraft.wiki.gg). Listed so the map does not show stones as a summon.
Confidence note
Confirmed (press, dev interview)