Summoning Stones is TBC and
NOT Vanilla.
Meeting Stones in Vanilla was used as Looking For Group Tool.
http://wowwiki.wikia.com/wiki/Patch_1.3.0Meeting Stones
Meeting Stones are located outside of each dungeon to help players find a group to adventure with in the dungeon. The meeting stone will try to find you a viable five-person group by looking for a tank, a healer, and so on. As time passes and you are unable to find a group, the meeting stone will become less picky about who it groups you with.
http://wowwiki.wikia.com/wiki/Patch_1.5.0-Meeting Stones have had their rules for what players are grouped with what other players relaxed. This means groups who use meeting stones (or innkeepers) should have their groups formed much more quickly than they were previously.
http://wowwiki.wikia.com/wiki/Patch_1.7.0-Meeting Stones
.A number of miscellaneous improvements have been made that should allow for better group forming when using the meeting stones.
.You will no longer be kicked from the meeting stone queue when a player declines a group invite or when inviting someone that is already in a group.
.You will now be informed that you have left the meeting stone queue when the group leader logs out.
.Tanks and Healers will now be immediately added to the group by the meeting stone when they are the 5th member of the group.
.You can now be added to a group by the meeting stone when that group contains characters that have disconnected.