What's the difference between USB 3.0 & 2.0 and which should you use?

The ports look the same, but one is much faster than the other.
Newspoint on MSN

USB 2.0 or USB 3.0? Know the difference before buying, or you'll be at a loss.

USB 2.0 VS 3.0: USB, i.e., Universal Serial Bus, is a standard with the help of which computers and other electronic devices ...
SlashGear

What's The Difference Between USB 2.0 & 3.0 And How Can You Tell Them Apart?

The Universal Serial Bus, or USB for short, was introduced in 1996 as a solution by technology giants like Microsoft and IBM. The idea was to make connecting hardware to computers less of a hassle and ...