Would resetting an iPhone wipe out everything on my YouTube acct?

I had to reset iPhone to factory settings. When I went to YouTube I was of course logged out but everything is erased when I logged in. All my favorites and my subscriptions and history. How can a reset affect what's in the account?

It can't. There's no reason why a reset of your iPhone would gulp your account.

The likely problem is that you have conflicting "cookies'' -- or you are mistaking
your YouTube account with your Google Plus account. They're not same thing.