Dis able: "user just logged in" and "publice streaming" without locking down the site

Hi,

Is it possible for me to create an article and not have it in any category but at the same time have the public viewing it? Please let me know how to do that.

Secondly, every time some is logged in it is viewable in the stream area. How do i disable this?

Third, i would like to disable public streaming without locking down the site?
Please let me.

Thanks
Anthony.