/mhoogkamer /lancefestivalen
You would not lose anything. You'd simply take over those accounts and start blogging from there. Anyone who wants to follow an old post would go to your old posts from Twitter, etc.
You would not be dropping those. If you don't want shorter / names at Chumly don't worry about it. I just thought that jan (or /lance) and /michael would be easier for everyone on the team to remember and type.
It's totally your call.