First, you have no clue who are the posters: white, Indian, Brazilian? But if you don't care about races of your roommates, you may give it a try. Second, those listings are similar to ones in any classified. They are not especially attractive in terms of rent, efficiency, location, etc. So if you don't want to risk having roommates from foreign cultures, why bother to hunt there? Anyhow, I still recommend you to take a look at the off-campus listings, as it can help you get a big piture of housing available in Toronto, and make an informed choice.

BTW, which program are you in?