Are We There, Yeti? - (Step 3) Take Umi's Mechanical Yeti and scare her friends with it:
Legacki in Everlook (Winterspring)
Sprinkle in Gadgetzan (Tanaris)
Quixxil in Marshal's Refuge (Un'Goro Crater)
When you are done, bring the Mechanical Yeti back to Umi.
Blackrock Spire Alliance Quest
Put Her Down Travel to Blackrock Spire and destroy the source of the worg menace. As you left Helendis, he shouted a name: Halycon. It is what the orcs refer to in regards to the worg.
Silithus Alliance & Horde
Into The Maw of Madness - (Step 2) Commander Mar'alith at Cenarion Hold in Silithus wants you to find his beloved Natalia. The information that you gathered points to Hive'Regal in the south as being the area in which you may find Mistress Natalia Mar'alith.
Do not forget to visit the dwarves at Bronzebeard's camp before venturing into the hive. They might have some additional work and advice for you.
And [Name], remember the Commander's words: "Do what you must..."