DDoS

On the Internet, a distributed denial-of-service (DDoS) attack is one in which a multitude of compromised systems attack a single target, thereby causing denial of service for users of the targeted system.
The flood of incoming messages to the target system essentially forces it to shut down, thereby denying service to the system to legitimate users.
A hacker (or, if you prefer, cracker) begins a DDoS attack by exploiting a vulnerability in one computer system and making it the DDoS "master."
It is from the master system that the intruder identifies and communicates with other systems that can be compromised.
The intruder loads cracking tools available on the Internet on multiple -- sometimes thousands of -- compromised systems. With a single command, the intruder instructs the controlled machines to launch one of many flood attacks against a specified target. The inundation of packets to the target causes a denial of service.

While the press tends to focus on the target of DDoS attacks as the victim, in reality there are many victims in a DDoS attack -- the final target and as well the systems controlled by the intruder.

ProxyShield DDoS Protection is a service that protects websites from DDoS (denial of service) attacks. The good of it is that it does not require you to buy any equipment, or change your hosting provider.
You can simply point your DNS to the Proxyshield network, and the traffic is scrubbed before passing clean visitors to your website.
Proxyshield was able to get back online famous milliondollarhomepage.com that was attacked during its peak by extortionists.
Considering how much it could cost an attack of this kind, it could be a very cheap insurance for many companies.