There was an old mmo i tried long ago, it was garbage but one thing stood out was the ability to carry a person.



http://img842.imageshack.us/img842/8572/18859571.jpg

It would enable one person to request an option to carry another somewhat like a trade request, once agreed to the initiator would be able to carry one to another point ( in some cases even jump/ or fly to harder to reach places, iirc). This along with a partnered dance option would add alot to the game i think.