I would deem meaningful consent...well, understanding, period. In fact, you can look at the recent amendment to PIPEDA in 2015. There's so-called enhanced consent, so read that. I have it chapter and verse in front of me. That's a pretty good description of meaningful consent. It's understanding what you're consenting to.
I'd just make a point about children. Even though there's a very useful rule such as COPPA, and there's a voluntary rule, essentially the same rule, in Canada articulated by the Canadian Marketing Association, those are useful, but, in my view, a minor can't consent.
You can treat it as consent, but they have the right to basically withdraw whatever consent they've given at the time they get to age 18 or 19. It's not exercised, but I think that is the legal rule, so they have an opportunity to re-evaluate it. I think that would work for this “right to be forgotten” for children, for example. They should get to re-evaluate it at age 18.