NetBEUI is IBM's transport protocol for its PC networking products. If the number of available protocols seems like senseless confusion, it is and it isn't. Certain protocols have different advantages in specific environments. No single protocol stack will work better than every other in every setting. On the other hand, much more is made about the differences in protocols than is warranted.
Proprietary protocols can be perfect solutions in many cases.
Besides, if proprietary protocols are sufficiently widespread, they become de facto standards, and gateways to other protocols are built. These include DEC's protocol suite, Sun Microsystems' Network Filing System and other protocols, and Apple's AppleTalk protocols. While these enjoy widespread use, that use is based on the computers these companies sell and not the proliferation of the protocols throughout the networking industry. Whether it's a proprietary or standard protocol, users are faced with difficult choices. These choices are made slightly easier by the shakeout and standardization that has occurred at the physical and data-link layers.