I as a Chinese know quite much about China govt's monitoring and censorship problems but would not like to emphasize on that.

On this lack of native WeChat app for Maemo, I guess only Hong Kong-ers and some other Asians want it (mainland China has too few N900 users, and WeChat isn't known in US and Europe), so guys you might as well put down hope for a native client. Not to discourage you but this is the truth. N900 is not faved by many devs originally, and its 4-year age adds further to its difficulties.

Better install NITDroid (Android 2.3.x) on N900 and try WeChat on that, may not be a good experience but yeah, it's better than nothing. If there's trouble in installing, I and others can provide a helping hand over at NITDroid forum and my name is still AndyYan over there.