Nobody knows what happened within the MMC Association in 1998
In 1999, some members from the MMC Association decided to split and create SD Association. But nobody seems to exactly knowwhy.
sdomi's webpage
I don't even know how to summarise any of this research, because it's not only a lot of information, it's also deeply bureaucratic and boring - it takes a certain kind of person to enjoy this sort of stuff, and I happen to fit the bill. This is a great read.