If I outsource a copywriter to get content on my site, then can I add myself as the author for the articles? For what pages do you use the author tag? What is the minimum number of words that would justify an article to deserve an author tag?
From what I remember in HTML 101, the author tag refers to the person that actually authored the web page, constructed the page, not necessarily the content on that page. I can see how this could be important for copyrighting purposes but I don't care to use the tag myself.
There is support for many authors contributing to the same website as well as rel="me" tagging. And not every article that uses authorship markup will see all the benefits, such as author photos in the SERPs.
I suppose you could claim authorship for ghost-written content - however, I wouldn't do it. One thing that Google is going here is building reputations for various author identities. I would suggest that playing it very straight is the best long-term strategy. As usual, YMMV. This is new territory.
Oh. Was whatson was referring to the meta author tag located in the HTML document's HEAD or something else? If so, this tag declares who is the author of the HTML document. Whatson can use this tag on any web page he has created regardless of who created the content in that page.
Google's attempt to associate writers with their content by using the rel="author" attribute is something else altogether. This new attribute to the anchor tag is suppose to appear on the hyperlink to the author, quite often at the termination of the article or as part of the introduction to the article.
Ditto what tedster said. Some implementations of the author markup aren't even valid HTML.
>> can I add myself as the author for the articles?
If you own the content, then I don't see why not. On the other hand, I think the whole concept of author tags is to help Google+. If you have any followers or any real presence on G+, then you might benefit from higher rankings for personalised search.
If you paid for the content, then there's no reason why you shouldn't take credit for it. Unless you have some kind of agreement with the actual author which prohibits you from taking credit. Either way, don't give an author markup to the author unless a) he has a G+ profile with more than an acceptable amount of followers (ie. more than you), and he will accept the work as his own;
If you don't want your competitors stealing your writers, I would definitely not make their information public. In fact, if I was a competitor, the first thing I would look for is who was writing for you.
My advice: don't do it. Mark it up with your own details or don't do it at all.