What exactly is that?
Hangouts on air is when you can host a Google hangouts session between a few select people and essentially provide the general public the option to view the stream (but not join). It's popular with podcasts, game streamers having discussions etc.
It's a feature built into Google Hangouts, but isn't Google Hangouts as a whole.
Is there a separate Hangouts on Google+ than there is for one's normal Google account?
Sorta, I guess? You can access Hangouts separately on hangouts.google.com, which I don't believe requires a Google+ profile (I could be wrong).
And "Facebook does the same" is not an excuse. Google+ is a competitor to the already established Facebook, it has to offer something different, otherwise, people won't switch.
Google+ did offer something different (circles, clean UI stream etc). But the issue with social networks is to do with user usage to become a self perpetuating reason in it self. There are many people that despise Facebook, but use it regardless because everyone else is there, including people that prefer to use Google+ over it.
The last time I checked, they got rid of it by allowing a pseudonym but requiring that the person choose a public name that included their real name. So I could be "Jason Levine (Pseudonym)", "Jason (Pseudonym)", "Pseudonym (Jason Levine)", etc. Not really helpful if you didn't want your real name publicized.
You might want to check out the Wikipedia page on Nymwars, while there are other better sources available, the article is a good summary of events and what has occurred.
(Yes, I realize that there's something odd about me complaining about a real name policy when I use my real name on Slashdot. I signed up for this account years ago when I didn't care if my real name was out there. I don't want to sign up for a new account so this is one of the few accounts I use with my real name and I never directly reference my pseudonym account.)
There is nothing odd about that.
Why the fuck do people keep going on about this. FACEBOOK has the same FUCKING policy.
I'm wondering why people are still going on about it when it's no longer a policy on Google+.
Gmail is email which is a standard and had protocols that support it.
OpenSocial is a standard that is supported by some major social networks.
Technological progress has merely provided us with more efficient means for going backwards. -- Aldous Huxley