Just got a targeted offer sent to me by Air Canada:
Earn double Miles when you fly between Vancouver and Beijing, Shanghai or Hong Kong for every round trip or two one-way fight segments. Simply register and book by September 23, 2013 for travel between September 9 and December 27, 2013.
You also can try to register via the link above but there are no guarantees you’ll get the mileage if you did not get the email but as is the case with most targeted offers it does not hurt to try and YMMV!