Every time you click on that shopping cart icon, you probably wonder queasily whether your credit-card information will be safe. Will you forever regret buying that musical burping bat-food dispenser shaped like a half-eaten grilled cheese sandwich?

You may or may not, but the scope of online shopping is expected to reach half a trillion dollars this year, says the Sunday Times based on the Internet research company IMRG.

The company says that more than a billion people, or 17% of the world population, uses Internet. Almost a third of them are in Europe.

Online sales in Britain are expected to total some £42 billion this year ($84 billion), which is roughly equivalent to Tesco's sales for the year. And that's Britain's biggest retailer.

By the year 2010, e-shopping in the U.K. alone is expected to reach £78 billion ($156 billion), or 20% of Britain's total retail sales that year.

Online sales in Britain took off during the last six years, but to be fair, so did Internet in general. That said, they roared with 3,550% growth from April 2000 to December 2006, according to the paper. During that time, online shopping expanded from £87 million a month to £3.6 billion a month.

The first online sale was a CD, in August 2004.