At this time, it is not possible to "post anonymously" when logged in. You would have to enable the "reply to topics" privilege to a specific category for guests, and then your users would need to log out to post as a guest.
I see topics and post question for newbie
I have a question : Can someone please point me in the right direction, to get this information?
In the acp, I am able to view the visitors and pageviews according to the time period, via the graph on the dashboard.
However, I am not able to see such a breakdown for user signups, topics, and posts.
Thanks for help