Had a 4-hour Mx delay in HNL a couple months ago, and they handed out compensation cards for 1000 miles.
The
Contract of Carriage actually specifies compensation of 2000 MP miles if your delay is 2 hours or more (applies to tickets purchased on or after 09 Jul 2010; prior to that compensation is only 1000 MP miles).
If your flight is delayed two hours or more, one of our airport Customer Service Agents will provide you with an Apology Brochure from the employees of Alaska Airlines and Horizon Air, which includes 2,000 Mileage Plan Bonus Miles to be deposited into your Alaska Airlines Mileage Plan account.