LilyPad is the best app you've probably never heard of. Similar to Facebook Chat Heads, LilyPad offers a pop-up window for all your messaging programs that follows you from app to app. When minimized, the chat windows take up a small amount of screen real estate, letting you make use of other apps knowing that your conversations are only a tap away. That means you can watch a YouTube video or surf the Web while simultaneously chatting via AIM, Yahoo, Jabber, GoogleHangouts, MSN and Facebook friends.
More: Best Smartphones 2013