Cloud Ddoser is a "Ddosing" program which works similar to "LOIOC" (Low Orbit Ion Cannon). This program will constantly check if a website is online or offline using your maximum processing potential and possibly bandwith. It's similar to refreshing a page over and over a million times; each time you refresh a page you are using the server's resources. If enough people are running this program on the same target you could potentially bring down any server.

To summarize: A more powerful version of LOIC can do a lot of damage if used on multiple networks/hosts. Ex: each one of your rat clients using this would do some serious damage