Akonadi (which is what you're probably referring to) *currently* requires
MySQL, its storage is abstracted so you could plug in a different storage
engine, however. The requirement is as simple as "right now mysql is the
During the beginning of Akonadi development, the idea was to actually use
sqlite, but it was very problematic. Sqlite could not, at that point
handle the number of concurrent queries such a high-performance cache
would need, it also wasn't thread-safe.
It seems that sqlite has improved in those areas, and work on an sqlite
backend is well underway. There's also work going on on a postgresql
backend, by the way.
All that has nothing to do with forcing people to use certain webservices,