While the official Maemo platform (led by Nokia) is not actively developed anymore, some 3rd party Extras and the Maemo Community Updates project (which welcomes helping hands) are quite alive.
MeeGo never managed to fulfil its own expectations with regard to openness and transparency and is also more or less dead.
Tizen (MeeGo’s successor) is still vaporware plus membership is mostly invite-only while I prefer transparency.
What is left and to recommend in this area is Mer, a community-driven project based on MeeGo with real open governance and trustworthy maintainers that know how to communicate.
Consequently I have removed my admin flag for MeeGo’s bugtracker (it feels unmaintained anyway) and unsubscribed from nearly all MeeGo and Tizen mailing lists.
I will continue to stick around in the Maemo and Mer communities (mailing lists, IRC, bugtrackers) as they currently feel like the places to be. Cheers!