Even Anti-virus sites have information about Conficker C, so this should be taken seriously. People using any type of network and people that use USB drives sound like they are more at risk. All it takes is one computer on a network to get infected, and it can infect all other computers on the network that are not protected. I would presume this could potentially even happen if someone with an infected computer tries to "piggyback" off of a wireless network. If the person piggybacking has an infected computer, it could possibly infect computers on that same networks, and possibly the reverse, as well. I have read that some people advise disabling Auto-Run on USB drives to prevent transmission of the virus. However, it is debated as to how effective it is.
Another thing I would advise is to avoid saving and typing sensitive information on public networks (school, library, etc), just in case the virus installs data-miners.