Thank you for your question. However, I'm not quite sure I understand what you are asking?
CNET, YouTube, TV Guide have all separate registration/login for their individual sites and they do not talk to each other or share that same login credentials. Essentially, if you register for CNET, it does not register you for YouTube or TV Guide and vice versa.
Maybe you are referring to CNET's YouTube channel? If you subscribe to the CNET's YouTube channel, you are registering on YouTube account and not registering for CNET as YouTube/Google are owners of that account of yours. We do not own YouTube. Does that make sense?
Bottom line all accounts from these sites are not interrelated regardless if you use the same or different email addresses for each.
If you can clarify your question and give me some context of what you are trying to do here. I may be able to help clarify things.
Thank you for your help.
I am signed in to a different email with CNet than I am with YouTube. How can I verify that I had indeed signed up for CNet and TV Guide, etc., on YouTube?