What is a "worm"?
Worms are similar to viruses except that they tend to attack networks and clusters of networks as opposed to individual computers. They don't need to attach themself to another file. They're not dependent on something else. They can actually infect a node, which is just a cluster or grouping of servers, and they do tend to infect servers, which affect many more people than just on a personal computer. If you can imagine, a server might provide services to thousands of people depending on what it is and what it's for. That worm has the opportunity to much more quickly affect those people than a virus, which is really more towards a personal computer. A worm acts very much like a virus can. There are many different kinds of worms. It could completely shut down an entire system. It could run an application. For instance, if it somehow got into a bank system or an airline system, it could run an application where it manipulates the time of air travel, or manipulates the time stamps on bank deposits. It's really an application that can do pretty much anything that the creator can imagine.
