There are two main types of USB:  1.1 and 2.0.  Version 2.0 is about 40 times faster than version 1.1.  It looks the same and uses the same basic external hardware.  It's compatible with the older version, and the older version is compatible with the newer version.  When you're using things like a USB mouse and/or keyboard, the difference is unnoticeable.  But when you're using things like a PDA, memory stick, or other storage device, the difference is painful.  USB 1.1 is extremely slow when transferring large amounts of data.  It's almost unusable.  But USB 2.0 is great for this kind of thing. 

My one complaint about USB is that the plugs are completely unintuitive.  Who thought of a symmetric plug that can only be plugged in one way?  Instead, they should've made the top wider than the bottom so the user wouldn't have to try to force it in upside down. 

Ok, one more complaint about USB.  The connections are often in hard-to-reach places:  The back of the computer; behind some hidden door on the front.  It's ridiculous, especially if you have your CPU on the ground and you can't see where you're plugging things into.  The smartest place for a USB connector was on the side of a Dell LCD monitor I had a few months ago.  It was easy to find and easy to use.  Its only problem was that it didn't work all the time.  I'm not sure why.  But it was a great idea. #technology