Android: What's the difference between a title bar and an ActionBar
Different thing.
TitleBar - small (usually grey) strip at top of screen that lists your Application Name (mostly not used anywhere)
ActionBar - the core navigation component of modern Android apps - this is where you will put the main navigation components (including actions on the things in your activity, a title explaining where you are in the app, Share links, etc); To support this in all modern Android versions, you will need to use a library to implement this. ActionBarSherlock is a very popular one, and there is now ActionBarCompat, which was released in the latest Support Library.
Bottom line, TitleBar should be disabled in favor of ActionBar for applications targeting modern design standards