re: APIs. dBASE is the classic example of how to utilize this (and how to ruin it later).
"Ed Esber, CEO of one-time database giant Ashton-Tate and makers of dBASE, became the target of such enmity from the dBASE development community. Esber owed his fortune to the developers of third-party dBASE products who took his usability-deficient product and created applications that people could actually operate. This didn't stop him embarking on an RIAA-style litigation campaign. At a Software Publish Association conference, Esber declared to a group of dBASE developers "Make my day!" while threatening to sue anybody who dared build a dBASE-compatible product."
There was a time when there were dozens and dozens of companies who primarily added functionality to Ashton Tate's product, rather than competing with Ashton Tate.
"Ed Esber, CEO of one-time database giant Ashton-Tate and makers of dBASE, became the target of such enmity from the dBASE development community. Esber owed his fortune to the developers of third-party dBASE products who took his usability-deficient product and created applications that people could actually operate. This didn't stop him embarking on an RIAA-style litigation campaign. At a Software Publish Association conference, Esber declared to a group of dBASE developers "Make my day!" while threatening to sue anybody who dared build a dBASE-compatible product."
( http://www.hacknot.info/hacknot/action/showEntry?eid=58 )
There was a time when there were dozens and dozens of companies who primarily added functionality to Ashton Tate's product, rather than competing with Ashton Tate.