The word "blended" is frequently very confusing when applied to whiskey, largely because it has more than one meaning depending on situation and type of whiskey and because none of those meanings really follows the colloquial definition. I think that most people who were not familiar with the term as it applies to whiskey would think, if they saw it on a whiskey label, that it meant that different casks of aged whiskey were blended together to form the mixture that was subsequently bottled. Well, guess what? Virtually all whiskey on the market is made in that manner, and it's not all labeled as blended. A distiller will usually find a significant variation in flavor and character from barrel to barrel; and if he wants to sell a consistent product, he has to blend barrels together to achieve the character that he's looking for. So, except for the few single-barrel bottlings out there, every bottle of whiskey on the market has been blended, using the conventional definition of the word.
With Irish and Scotch whisk(e)y, though, a different definition is used. Actually, one of two definitions. A blended Scotch whisky is a whisky that has been blended from malt Scotch whisky and grain Scotch whisky. Similarly, a blended Irish whiskey is a whiskey that has been blended from malt Irish whiskey and grain Irish whiskey. Alternately, one could have blended malt Scotch, which is a blend of malt Scotch whisky from different distilleries (ie, what used to be called a vatted malt before the Scotch Whisky Association decided to stick its nose into labeling requirements). In Ireland and Scotland, grain whiskeys are column-distilled to a very high proof (usually close to 190) and usually derive almost all of their character from the barrels that they are aged in.
American and Canadian blended whisk(e)y are different beasts altogether. The United States has a concept of straight whiskey, which is a whiskey distilled from a mash of at least 51% of a particular grain to not greater than 160 proof and aged at no greater than 125 proof in new charred oak barrels for not less than 2 years. American blended whiskey is a blend of American straight whiskey and either grain neutral spirits (ie, spirits distilled from a grain mash to greater than 190 proof) or "light whiskey" (ie, whiskey distilled to greater than 160 proof but less than 190 proof, aged in either new or used oak barrels). Canada doesn't have the concept of straight whisky, but their approach to blended whisky is similar: they blend "flavoring" whiskies that were distilled to a relatively lower proof with grain neutral spirits. In other words, when you see the word "blended" on American or Canadian whisk(e)y, it usually implies a fairly hefty dose of grain neutral spirits in the bottle and a spirit in the glass that is light and subtle in flavor (not always -- it's possible under US liquor laws to have a blended whiskey that is a blend of entirely straight whiskeys, but you can bet that if such a thing ever came into being -- I don't know of one on the market -- it would be labeled in a manner completely different from plain old cheap American blended whiskey). The standard disparagement for these blended whiskeys is that they are "brown vodka" -- largely flavorless and characterless and distinguished from that other flavorless and characterless liquor only by their color. (Note that it's not the case that the bottler just takes aged straight whiskey, adds in a dose of grain neutral spirits fresh off the still, and bottles it. The grain neutral spirits have to be aged for a period of time, too, which means that they lose some of their neutrality.)
Virtually all Canadian whisky sold today is blended. Up until a few weeks ago, I would not have qualified the "all" with "virtually". I had never recalled seeing a Canadian whisky that didn't have the word "blended" on the label. Then I looked closely at the label of Forty Creek Barrel Select Canadian Whisky. "Blended" isn't on it. That's significant. The verbiage on labels of spirits sold in the United States is tightly-regulated by the BATF, and the BATF regulations distinguish between Canadian Whisky and Blended Canadian Whisky. The fact that Forty Creek does not have the word 'blended" on its label is significant. And, in fact, once you look at the matter more closely, you'll find that Forty Creek is in fact very different from the standard Canadian Whisky distiller. Forty Creek is produced by Kittling Ridge Distillery in Grimsby, Ontario, just a hop, skip, and jump from Niagra Falls. The owner, marketer, and master distiller is a former winemaker named John Hall. He owns two German-made pot stills that he uses for all his distillation. His whisky is made from corn, rye, and barley malt, and each grain is distilled and aged separately (usually -- Hall also likes to experiment), then blended together to make the whisky that goes into the bottle. Most of his whisky is distilled once to around 62% alcohol, but some is doubled to 70-75%. And therein lies the reason why this doesn't have to be called blended Canadian whisky: none of its constituents comes close to being 80% alcohol. Nothing close to neutral goes into the whisky; therefore, it doesn't have to be called blended.
It still is Canadian whisky, though. It's not as bold or assertive as American straight whisky. The nose is fruity and nutty (the latter due to the finishing that it gets in ex-Sherry barrels, the Sherry having been made by Hall himself) with some vanilla mixed in. It goes down light and smooth, without a whole lot of flavor. There is a difference of degree, not style, between it and other Canadian whiskies. It's not bad, but it's not mind-blowing.