I don't know but you can use private or incognito mode, or different browsers (Firefox, I.E., TorBrowser...) to be logged in differently. NoScript can block pop

I don't know but you can use private or incognito mode, or different browsers (Firefox, I.E., TorBrowser...) to be logged in differently. NoScript can block popups, may glitch site. Edit: For Youtube, if you turn on safe mode, hiding comments, it may prevent the box talking about the new comments section, but now I do not see see it with it off, so I may be wrong.