Vanessa was the CEO of an online bookseller. Her company made thousands a day in sales, but with shipping costs rising, each day of business just barely kept her afloat. Therefore, Vanessa was horrified when one day she got an anonymous email threatening to shut down her website unless she paid the sender a large amount of money.
Vanessa checked with her IT department and found that the company was indeed vulnerable to such an attack. The attacker could easily create a network of "zombie machines" that would send way more traffic to her site than it could handle, effectively crippling it. It would take weeks to install the necessary security measures to protect the site, and Vanessa couldn't afford to be shut down for that long.
Vanessa paid the money the attackers asked for, and then spent twice as much getting the site's security up to date so that this sort of thing couldn't happen again. "The next time somebody tries this, they're not getting any money from me," Vanessa says. "I just wish I had known about this threat before."
To learn how to protect your website from denial of service attacks, see Web Publishing - Denial of Service