Yes, a lot of people have moved to Tumblr. It isn't the best way to discuss things. And for a while Himaruya did not work on Hetalia (possibly as he was shifting from Gentosha to Jump and working on other projects in between).
The newest scanlations are posted here as soon as the translator group is able to finish them.
They are, of course, backed up on Hetarchive.net/scanlations.
I think the active fans are just simply more active on social websites like Tumblr and Facebook currently. Hopefully with the new posts more people will be inclined to post here.