Kelly McNeill writes "The Microsoft definition of scalability means, "You can add more servers any time you need to." The IBM definition is "You don't need to." It's that simple.
For those who are unaware of the scalability limitations of obsolete, legacy environments such as Windows NT and 2000, it is best to let Microsoft speak for itself. According to company literature, a so-called "heavy user" scenario -- involving "full-page documents using Microsoft Word" and "even heavily browsing the company Intranet" -- on an NT-based Windows Terminal Server network requires a dual-processor Pentium II with 512MB RAM, but it is recommended that there only be 15 to 25 users per processor."