Thanks so much for the update with the option to choose between sharing or syncing! I am having trouble, though- I checked the sharing box so that I can make posts to Facebook and re-converted all my mobi files to new ones with the ASIN removed (verified on mobiperl) But, after replacing all the files on the Kindle and rebooting for good measure, I am still getting the unable to share content message. Any ideas? Did I go about it wrong? Or maybe Amazon has disabled posts from personal docs?