> for example, by using its own mail server.

I was one of the people fighting for keeping Unix when the UU went to Exchange. It was a drama: instable af, the MS consultants could not keep it running even for 24 hours at a time while unix had 0 issues and kept chugging along (I don't remember what Unix: I think it was SunOS/Solaris). It was forced through at great cost and effort but of course sponsored by MS. It sucked for years to come.

I was at the UvA too when they moved to, equally instable MS stuff too: I worked behind some of the last Sun machines and got to take a palet of sparcstations, ultras and an e450 home when they got phased out (I still have them and they are still working, of course). Could have all been Linux now but MS was so aggressive and no one listened to profs or students, even in all tech deps who were all vehemently against the move.