For the record: about 2.5M of these 5.6M users on matrix.org are native to Matrix, rather than bridged. the 50% guess comes from the fact we see 8M in the phonehome stats right now (including the 5.6M on Matrix.org) so that gives 2.5M on and 2.4M off. In practice the number off would be much larger given lots of bigger deployments we know about don’t phone home.