The DrDolittle guy is (unless someone else managed to obtain not only the 2 accounts on here but also the original BLK address) rat4, the original developer of BlackCoin.
While he used to communicate with the community and other developers in the past, he suddenly ceased to do so.
Other devs, most notably janko33, started to build a new wallet, integrated colored coins, atomic swaps and so on on top of the original BLK protocol - w/o rat4/DrDolittle - as they had to assume that he abandoned the project (read the posts of the last days to get a feeling for it).
Totally out of the blue rat4/DrDolittle announced that BLK will no longer be BLK and is going to be forked into "BlackNet", obviously assuming that everyone, including exchanges and the community, will follow.

Current situation is:

1. BLK will continue according to the plans and works of janko33 and his group, with BLK being updated to include the improvements from the latest bitcoin core base. That version of BLK will (also) require a fork but stick to the current BLK PoS protocol that is proven by BLK itself and a couple of thousand forks. We do believe, that that version will stay listed on the exchanges.

2. rat4/DrDolittle will at some point "take a BLK snapshot" and fork into his "new Blacknet", though nobody but him (and maybe his secret circle) knows what that is going to mean, what technology it is going to use, if and how it is going to be tested in public etc. You can at this point only obtain Blacknet coins/token/whatever by holding BLK at the moment of the not yet announced snapshot.

Hope that helps,
@janko/gritt feel free to correct me if I am wrong with anything, due to family stuff I could not follow our gitter and other sources closely.

this post is also copied into the new BLK thread.