Yeah, it does work, both in emulator and mobile device. You should keep following things in mind while working with SharedObject in FL:
1. Use a listener object event handler when reading the SO
2. Make use of getSize() method to determine whethet the data exists in SO or not
3. Reading/Writing to SO is slow on mobile devices so, you might want to give it some time by giving 1-2 frames interval
4. Store the returned value of flush() method; it returns 'true' if data was successfully written, 'false' if not written and 'pending' if it is taking time
5. Most important:
- You CANNOT share SharedObject data between SWFs even if you have given same SO name. One SWF can access it's own SO, if you create a copy of the same SWF then also it would not be able to pick the same SO.
- The SO changes everytime when you publish and deploy the app on a device.
There is a very good article on DevNet about FL SO: http://www.adobe.com/devnet/devices/articles/persistent_data.html