When we started GNU FM, there were no clients which could scrobble to sites other than Last.fm.
Since then, the situation has changed.
For the latter option to become a reality, we need more people to set up and run their own GNU FM sites. We can then ask client developers to support freeform scrobbling.
Jonas Haraldsson has put together a wonderful resource of client support on the Libre.fm wiki. While much of it is specific to Libre.fm, please help us gain support for freeform scrobbling.