1 You can't reply to comments even on YOUR OWN VIDEOS
2 you can't post comments
3 You can't even VIEW YOUR OWN INBOX
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4 You can't PM people
5 If you channel is monetized then I have heard reports this screws it up.
In addition some other material relevent to this:
Google apparently think themselves 'above UK law'
I just wanted to see what you guys made of this