Best practice for Meta-Robots tag in categories and author pages?

[Lobtec]

For some of our site we use Wordpress, which we really like working with. The question I have is for the categories and authors pages (and similiar pages), i.e. the one looking: http://www.domain.com/authors/. Should you or should you not use follow, noindex for meta-robots?

We have a lot of categories/tags/authors which generates a lot of pages. I'm a bit worried that google won't like this and leaning towards adding the follow, noindex. But the more I read about it, the more I see people disagree. What does the community of Seomoz think?

[evilopinions1]

Category and author pages definitely create duplicate content. Category pages and tag pages are nothing but excerpts from post in that category.

However imagine a very old post gets a new comment. In order for you to get this indexed - it would be a good idea to leave the categories as to be followed.

However the archives serve almost the same purpose as the categories. Hence noindex nofollow for archives could be a good idea.

[Lobtec]

I was hoping for some more input regarding this. I appreciate your input David and will change the meta-robots around a bit. But thought I would get some more input, perhaps someone that wanted the categories to be index, follow as I have heard somewhere else.