Maemo 6 (codename Harmattan) is the next version of Maemo, which is going to power the next Nseries device and N97/N900 successor - most likely to be called N9 - expected in late 2010. The marketing department decided that in light of the MeeGo announcement, the Maemo name is just not cool any more, so it lost the Maemo moniker and currently has the *provisional* name of MeeGo-Harmattan. Harmattan will implement the MeeGo APIs so it will be a bridge/transitional release between ye olde Maemo and MeeGo (what every sane marketing person will deny as nobody likes transitional releases).
For Meego, at least people seem to know how to spell it. Not so for Maemo
If Nokia sends me there new MeeGo Device as an Excuse i will maybe use it .. sorry but to spend again much Money into a Device thats maybe abandoned after a few Months becouse Nokia thinks well our next high end Operating System will be xxx i wont do this failor twice.