After “Save a Friend” you can click the Conch to recruit one of three Ally companions who will fight alongside you each day. These Ally companions may only get experience from the Ally daily quests. There are only 3 of these quests available per day, and reward 100 Experience each. Basically, 1 rank per day.
Ally companions can max up to Rank 30. At that point, each of the three Ally companions that reach level 30 reward a different mount. These are the quests available at different ranks.