Comment 5 for bug 542734

Ok... as of today's patch, I can confirm that I can now add my twitter account and if the permissions on /dev/shm are modified, everything updates properly.

sudo chmod a+w /dev/shm

That probably won't survive a reboot. Guidance on how to make the mod permanent, along with a discussion of trade-offs is here:

https://help.ubuntu.com/community/StricterDefaults