I've never used the author tag, or even joined Google+, but as I understand it, Google's intended purpose for the author tag is to identify well-known writers, experts, and authorities. So if you write under a famous pen name, then it seems to me that you should be allowed to use that as a "nickname". But if hardly anybody has ever heard of you, or knows who you are, then I don't see what you would gain by using the author tag.

As for the date, I suppose that would be the date when you uploaded the article to your website for public view.

you certainly read a lot about the expected importance of the author tag on the SEO blogs.
and I would like to participate in that in the sense of claiming my content in helping to establish myself as an authority in my field.
I just find it so offensive that google confuses the issue of authority with real identity.
There are so many reasons why a person would want one layer of annonimity between their privacy and the ruthless exposure of the web.
I'm just curious if the nick name feature provides that.

A large portion of this planet ( Europe) has taken advantage of the "right to be forgotten" order.
Compare that to Eric Schmidt's comments a few years ago saying that possibly after years of youthful indiscretion a person should just change their name.
It's good to see google having to buckle under what the world wants vs what their pious stance has been.
It seems that the new nickname and pseudonymn policy of google plus may reflect that.

I must not understand it, because if you use a nickname to hide your real identify, then how will people who see your nickname in the search results know that you're an authority? Wouldn't they have to see your real name to know that? I already mentioned the only exception that I know of, which is someone who writes under a famous pen name.

People who are an Authority under their own name can continue to use it. Others are unknown by their own name but well known under another name or nickname. Now they can use that Nickname.

I have a group of sites in several very different verticals. I really would not want to be required to put my own name on some of them because of stereotypes. I have an extensive family background in some very "masculine" verticals (like construction widgets) but I'm not a guy - no one would ever visit my most popular sites if I had to associate them with my name and Google Profile (at least they took off the profile pictures) as author name. My sites have accurate contact information that is generic enough for public consumption. The Author and Profile issues are the main reason that G+ gave me the creeps. I still won't use it because I don't know that they won't change their mind later.

For people who write, there may be a number of reasons why they don't want strangers looking them up personally. If your name is uncommon, you're easier to find. Many years ago I had a couple from over 1400 miles away show up at my gate to buy a custom made item that I sold - the wait time after ordering was 2 - 3 weeks. I did not have offline card processing facilities and their trip was a complete waste for both parties. Details were on the site, they didn't read. (they did order when they got home..) I have been more careful since then. Each webmaster should know what information they want to put online and the public can decide how important that is for them.

I don't really think that in most cases a person's real name necessarily indicates much anything about web content authority.

If your name is Matt Cutts, then yes I get it. But if I'm just reading about SEO, most of the names I see aren't going to mean anything to me anyway.

Now, if know a person's name from having read their pages before, and know what they write seems to be good advice, then when I see their name in the SERP's I probably will be more likely to click their content. But I don't care if the name shown is Harry S. Truman, Harry S. or just Mr. T.

Even with the Google system, authority comes from the way your content is received by others ("circles", "pluses" received). It doesn't have anything to do with what name is used.

The whole name thing is just tied to (a backward method of attributing) accountability. The name you use doesn't count anything towards authority. Google isn't checking to see if you really do have a diploma. How many kazillion fake Google+ accounts are out there using the author tag?

I read a blurb today on SERoundtable about a google "learn more" attribution for the rel=publisher tag.

I would much much prefer my website being recognized as the "authority," as opposed to me personally. I would love it if either publisher (website owner) or content writer could be designated as the "author."

This is exactly the way it is with US copyright law. It's called a "work for hire." What's the difference between me, a writer, insuring that my content is good, vs. me the publisher insuring everything on my website is good.

Does putting a Google authorship tag on your articles miraculously turn you into an authority?

What about people who are already well-known authorities but haven't yet used the authorship tag, and most likely never will?

I still don't understand how it's supposed to work.