Could someone please explain the difference between Ethernet and usb. is it for speed? I'm about to install broadband and i know my pc has a Ethernet card i'm wondering if i should use this

USB - Short for Universal Serial Bus, an external bus standard that supports data transfer rates of 12 Mbps. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards. USB also supports Plug-and-Play installation and hot plugging. Starting in 1996, a few computer manufacturers started including USB support in their new machines. It wasn't until the release of the best-selling iMac in 1998 that USB became widespread. It is expected to completely replace serial and parallel ports. Ethernet - A local-area network (LAN) architecture developed by Xerox Corporation in cooperation with DEC and Intel in 1976. Ethernet uses a bus or star topology and supports data transfer rates of 10 Mbps. The Ethernet specification served as the basis for the IEEE 802.3 standard, which specifies the physical and lower software layers. Ethernet uses the CSMA/CD access method to handle simultaneous demands. It is one of the most widely implemented LAN standards. A newer version of Ethernet, called 100Base-T (or Fast Ethernet), supports data transfer rates of 100 Mbps. And the newest version, Gigabit Ethernet supports data rates of 1 gigabit (1,000 megabits) per second. "Want to make your computer go really fast? Throw it out a window."

If I was you I would use the Ethernet port and not USB. I've found that using Ethernet is a bit faster and you're not wasting a USB port. Save your USB port(s) for other equipment. I've used both Ethernet and USB for my broadband and I was much happier with Ethernet.