How to help the hackers.

• Position: THE WEB - Brief article

It's the digital version of leaving a key under the doormat: picking simple, easily guessed passwords. Yet one out of five Web users does it, says Amichai Shulman of Imperva, which makes software for blocking hackers. Shulman studied a list of 32 million passwords that a hacker store from RockYou, a site offering social-networking tools. Nearly 1 percent of the list used "123456," and 20 percent chose from a poor of the same 5,000 passwords. This makes it a tot easier for hackers to break into accounts just by trying the most common passwords, often firing off thousands of tries per...