There are thousands of member profile pages on my forum site. Should I let Google bot index member profile pages?. I am kind of scared that Google consider member profile pages as duplicate. Will I get banned for this?
don't bother about it. google will not ban by just duplicated content. However, if you scare of wasting bandwidth, yes, u shall not allow google to index it.
Yes, I think it helps. Your members will appreciate your efforts and may in turn to refer more members to your forum
I see no reason why you should stop Google from indexing your member profile pages. As long as they all don't look the same, same avatar, home page, same interests, location. sig..., you are not in any danger.
Will you actually gain anything from getting google to index those pages? If you have very good and valuable information there,Google would love to see it ..if not...well...
I suggest customizing the profile pages a bit - add questions, especially the kind that require more then a 1 word answer. Change the look of the page too.