Very unbiased. Only sampled people who were online and ostensibly only those who used Facebook. Since maybe ~60% of people use Facebook, I don't think the results speak for _all_ Canadians. If it did that's saying a lot for secondhand effects of social media platforms.
You don't get "points" for making some hypothetical claim. If you think there is something wrong with an analysis, demonstrate it. Isn't that what "pro-science" people do?
And therein lies the problem with online polling. The randomness, or lack thereof, is not demonstrable without polling people who did not respond to the poll, via a different medium. Hence the standard disclaimer.
It's not a facebook poll, not sure why you thought that. It was a poll taken from a random (presumably population-reflecting) sample of Leger's online polling platform. It's not technically a random poll like wardialing in the 40s got you but it's not just an opt-in facebook poll either.
Without access to the questions I don't know exactly who would have a tendency to respond. But would you answer a poll about how a service is affecting you if you didn't use it? And if not, that's my point -- that both the article's title and contents seem to speak for Canadians en masse but is likely not to, because it likely only sampled the 60% who use Facebook.
I really don't know why you'd assume people wouldn't tbh. Yes, I am (approximately, at least) a non-user of facebook and if I were being polled about it I would answer a question about my views on its effects on society.
Also, the most pertinent question to this discussion is in the post by the polling company I linked to above.
