There's some definite confusion going on. Let me see if I can give a shot at the various things we're talking about.

First we have the two questions:
Do you want to be visible on the "Who's Online" screen? Yes/No
Do you want users to see the actual forum/post you are looking at? Yes/No

1- If you go to the "Who's Online" screen, there's a "Registered users" section and an "Anonymous Users" section
2- if you are not logged on, you will show up in the anonymous section
3- if you are logged on, and have answered Yes to both questions, you will show up in the registered section, and everyone can see what you're doing and where you are doing it (as far as the BBS goes)
4- if you are logged on, and have answered No to the second question ("...see the actual forum..."), you show up as a registered user and people can only see what you are doing (viewing/replying/making a new post)
5- if you say No to both questions, you don't show up on the "Who's Online" screen at all


I think most people here (like me) thought you were talking about the people who were showing up as anonymous users in the bottom section of the "Who's Online" screen.