USB Cable Length Limitations:
The USB specification limits the length of a cable between USB 2.0 devices to 5 meters (or about 16 feet) and for USB 1.0 the limit is 3 meters (which is about 10 feet.) This means you can't just connect a bunch of extension cables together and run them 30 feet to another room. However, you can connect a 6 foot and 10 foot cable for a total of 16 feet.
In order to go beyond these limits you need to use USB hubs, USB active extension cables or USB over Ethernet products.
You can use extension cables and up to 5 USB hubs connected together to extend USB's range up to 30 meters (up to 27 meters for USB 1.0 devices). The distance between each hub can be no more than 5 meters.
Active Extension Cables:
USB active extension cables contain electronics which regenerate the USB signal. These cables are essentially 1 port USB hubs and will allow you to go up to 30 meters (up to 27 meters for USB 1.0 devices) by connecting up to five active extension cables together (4 cables if you are connected to a USB hub).