It has NOTHING to do with the area codes 416 and 647, but about how Toronto was formed. Up until 1998, the city that is now Toronto was broken up in to six different cites; Toronto, Scarborough, North York, York, East York, andIn 1998, the Government of Ontario decided to combine the six cites, proposing it was a cost saving measure. As a result of the amalgamation* Toronto is now one big city, and currently the 4th largest city in North America, behind Mexico City, New York, and Los Angeles. Toronto's ahead of Chiraq by like 85,000 people or something.
Even though the former six municipalities are technically all Toronto, they are still referred to as their original names. Reasons being that a lot of street names are repeated so, to identify your location, a "borough" is needed.
Example, your mail would say Scarborough instead of Toronto, if you live in that area."the 6ix"