why not? right click someone's name and browse user files.
only thing that should prevent you from doing that is if there are firewalls in play or if the person doesn't share files outside of their friends list.
i haven't got a virus from it ever that i've known of.
i only use it for music though so i can't say for movies etc
joining a room just helps you to narrow down your searches to people with more common interest because you can do room searches for songs/albums. you can do servew wide searches too or searches of your user "buddy" list as well
it has been the best source for DL'n music for years now in my opinion
once I get my movie burned ill join, I have a 160 mb hard drive and I have 130 of it full, I need more music though, if im on there check me out. ill be on at 7:00 western time.