What a bold move. There are other in the OS communities, languages guru's that are working 100% on the language?
Matz is working only on ruby at heroku? Guido, is working full time at dropbox?
I think this is huge lose for Facebook and a big win for D lang comunity
FaceBook has Simon Marlow working haskell though it seems he's mostly working on the library side of the things see[1].