This decade is the decade of gadgets.
From the tiny USB thumb drive introduced in 2000 to the iPhone 3G in 2008, a bunch of revolutionary devices have been brought to the market.
Check out the 15 best gadgets of the decade →
Of all the contraptions sold between 1999 and 2009, mobile phones were the most popular. At the turn of the millenium about 1 billion people worldwide had cellphone subscriptions. Today it's closer to 4.5 billion.