A USB hub is a special device that can greatly expand the number of slots available to you for USB ports on any computer. Generally your computer will only come with a few USB ports available. This is especially the case when it comes to laptop computers, that classically only have around 2 USB ports.
USB ports are needed for just about every device you can think of that attaches to your computer including cameras, external stereos, scanners and a multitude of other devices that you might need in your studio.
If you don’t have a USB hub currently, then you will be severely limited to how many devices you can use at once through your computer system. Adding new USB ports directly to your computer to allow for more musical devices, such as instruments that have USB hookups, but it would be a needless expenditure.
USB hubs are cheap and easy to use. All you have to do is plug the “upstream port” directly into one of your USB ports, and you will get a number of downstream ports equal to the number available on the hub. USB hubs range in extra ports from just a few for the cheaper ones, to many, many ports, that will allow you to outfit every aspect of your studio.