What is a Server?
A server is a system that responds to requests across a computer network to provide, or help to provide, a network service.
In Information Technology:
A server is a computer program that provides services to other computer programs (and their users) in the same or other computers. The computer that a server program runs in is also frequently referred to as a server (though it may be used for other purposes as well).
In Client/Server Programming Model:
A server is a program that awaits and fulfills requests from client programs in the same or other computers. A given application in a computer may function as a client with requests for services from other programs and also as a server of requests from other programs.
Servers often provide essential services across a network, either to private users inside a large organization or to public users via the Internet.
By adding a server to your network -- you reduce the likelihood of spyware and viruses impacting your business data, as long as you run strong antivirus software on the server. Also, by adding a server, you can benefit greatly from these features, especially considering the data protection available in a RAID Array.