This is a big topic that attracted a lot of discussion on this thread:
Gamma issues with .mov / colorspace metadata in Quicktimes / NCLC tags
Changing the ColourSync profile on the mac is an interesting approach. I can’t remember if this was mentioned but maybe there is some useful info.
Funny thing is i don’t think that fixing the ColourSync locally would change how other people see it? The major problem is how do you control the look of your media and the general consensus was that it is pretty fucked. Especially when you consider that media might get uploaded to YouTube and Vimeo and get viewed on a Mac or PC.