In common parlance, when people post personal information on a social media platform and allow certain other people to see it, one might think that this information becomes public. Importantly in this context, one might also think that companies and commercial organizations could use this information as public, rather than personal, information. However, the current law provides that this information remains personal and cannot be used by companies, except in accordance with the law.
I think this is a good aspect of the current law, and the fact that nothing in the current text of Bill C‑27 changes this is a good thing.