If you are in the app and press the "back" button to exit the app, upon returning the timeline position is remembered. But if you press the "home button" or switch to another app using your "recent apps" button, then the timeline is not remembered and runs in the background while your not using it. Going back to seesmic brings you back to the newest tweet instead of the last position you have had. This is the non pro version on the Galaxy Nexus