The N9 doesn't seem to be popular enough around here to kill off the N900, although many of the notable developers haven't expressed an opinion on it. They (sensibly) tend to keep out of the popcorn threads. I'll be getting one, though it won't completely replace my N900. For myself and other application developers, it should be fairly easy to target both platforms, although some applications will take advantage of N9-specific features, such as NFC. It's the low-level hackers whose work is more likely to be exclusive to one platform, and there is a chance that some of them will focus on Harmattan. However, it seems to me that they are the people that are most stongly attached to Maemo (plus l33t haxors need a HWKB ).