Jens is the primary authority on Snap! itself. Michael is the primary expert on the forum. Bernat is the primary expert on the web site. All of them have dealt with the cloud back end, but if I had a question I'd start with Michael I think. Joan has been contributing mainly to Snap! itself. Jadga has mostly contributed to the SAP MOOC development. As for me, I'm a dilettante, but a lot of the user interface design for things like gray rings, the make a block dialog, the long form input dialog, etc., are my doing. And I'm the one who knows about languages other than Smalltalk, such as Scheme, Object Logo, and APL, all of which have contributed major design elements to Snap!. (Design elements from Smalltalk are Jens's work.)