Paul Mooney mentions a quick Admin tip in regards to broadcast in this post. Being able to broadcast via a dialog box popping up on the users desktop is a nice feature, so nice in fact that Lotus included it as an option via a check box in the more recent versions of the Administrator Client (at least in 6.5.2 - as we jumped from 5.08 to 6.5.2, not sure where it first showed up).
Another nice feature in 6.5.2 is the web administrator. Looks very much like the client itself and even allows one to view all of the notes.ini from the web administrator itself. Cool!