A winmodem is, quite simply, a poorly-designed sound card connected to your phone line. Instead of having some cheap chips generate the waveforms needed to transmit information to the other side, a winmodem utilises your computer's CPU to do the job. While it makes the modem only slightly cheaper to manufacture, it makes your computer much much slower (presumably an advantage to a hardware manufacturer). It also locks you into a particular OS, since drivers are typically provided only for the most popular systems available when you buy the modem. It means that it won't work with a real OS (like *BSD or Linux), but it also means a lot more (less?). Do you really think drivers will be available in 2005 to run your winmodem from Windows 2003?