Hiiiiii Guy a Guest has posted in my forum i dunno how even they don't have permissions and even my site was not advertised also my site link is www.techyden.com in that in introduction section in the topic welcome black ash see the black ash is posted as guest :'(
Are you sure the member didn't register than delete their account?
When a member deletes his or her account, it changes there posts as if they were "guests".