Back in the old days when someone appeared on your TV they would say something like "Thank you for inviting me into your living rooms", it was a nice way to acknowledge that they may be a strange face appearing within your home. I really feel that way about websites and online videos too.
When I visit a site or watch a video, that's a choice to invite that person, or the thing they create, onto my computer and I very much expect them to behave themselves while they are here
Particularly with videos, I really don't enjoy it when a stranger appears in the video, that's very in-appropriate! I invited a particular person onto my computer and now they are showing up with strange people I don't know

If friends did that in real life you would not want to invite them over anymore.
So I spend a lot of time when Im creating pages thinking about how visitors are going to feel about that page, is it a personal space or a public one, and what sort of things are appropriate because of that.
Sites can have all sorts of personalities within them, the author is of course one personality, and OCs on the site are like abstractions of the author; but I also feel that UI elements have personalities, buttons become like people you know, and old layouts are like old friends.
This all comes to mind because the new nav bar is a stranger here, and I've been thinking about what spaces its appropriate for it to appear within, and what places it should not appear. On TamaNotchi for example, I don't think its ok for mr Nav to appear because that site is its own world even though most people in this world know about it.
ANYWAY, all of that is a ramble to ask, how do you feel about the presence of people and new things online, on sites, in community spaces and on youtube. What kind of spaces are you ok to encounter strangers, and what kind of spaces do you expect to be more personal?