I have a Belkin N300 WiFi USB adapter. If I plug it into my PC running Ubuntu, clicking on the network icon in the "system tray" lets me select a wireless network to connect to and enter my network password. It just works without any hassle.
If I plug the same adapter into a known working USB hub on the Parallella, and then click on the network icon, the menu shows "Ethernet Network disconnected" and "VPN Connections". There is no "Wireless Networks" section of the menu.
What does it take to get a wireless connection working?