The update that went live on the 18th left an unknown proportion of RT tablets unusable
http://www.notebookcheck.net/Microsoft-pulls-Windows-RT-8-1-update.104414.0.html
Even Apple with their divine arrogance quickly re-installed Google's Navigation application (iPhone 4, I think). I hope Microsoft learns it's not a monopoly world, as much as MS owns much of its earlier success to that. I also hope that Facebook runs the same course once they run out of things to steal.