For the first time domestic home buyer in Toronto and Vancouver (especially Toronto), this is probably the single best piece of news they could have received. WAY more impactfull and meaningful then a $4k rebate on land transfer tax or anything of the like.   
Should interest rates increase (when, not if) to a level that forces already over leveraged owners to sell, and BAM we will indeed see the correction or bursting of the bubble as many have predicted with an increase of supply and greatly reduced pool of qualified and available demand.