Just a quick note that the Twitter client built into the Nokia N9 has had an official update pushed to it. There's no official changelog, but I'd guess on compatibility fixes after Twitter's well publicised change in authorisation and APIs. To check your N9, go into Settings>Applications>Manage applications and then tap on the right hand update tab. Screen proof below.
Here's the new Twitter update, pushed by Nokia's N9 support team; the new version is v1.3.9 and installs in seconds. No reboot is needed.
As usual, Twitter is fully integrated with the N9 homescreens; and, as usual, there's no respecting the AMOLED screen and dark theme once you get into the Twitter app itself. Ah well. Sigh.... At least it all still works....