See List of Tanaris NPCs.
He starts the following quests:
Once his quest chain is completed, he will sell Noggenfogger Elixirs.
This section concerns content exclusive to Cataclysm.
In Cataclysm, Marin has married Sprinkle and become the new baron of Gadgetzan. It is unknown how exactly he came to power. It may be because of his famous "drink".
In Legion he will become one of Rogue, Champion with the other Uncrowned.