Businesses continue to spend billions of dollars each year to defend their networks. However, Web applications remain a vulnerable point in the defenses. The Web application firewall (WAF) is one security technology that can protect Web sites by analyzing and controlling application layer traffic and sessions. While the demand for WAF is unavoidable, the ability to properly deploy WAF has been limited to enterprise organizations. But the market is growing and evolving as vendors simplify the process to buy and deploy WAF.