Most of the Operating Systems now a days offers search within it, Linux is modern desktop which offers many more features than any other Operating System. Ubuntu Unity has its Dash, Gnome Shell desktop also has integrated search, Whisper can be used in Xfce, KDE also offers search from menu, Mate and Cinnamon desktops already have this feature. Mac yosemite introduced new spotlight, it is an productivity feature available in Mac OS. But there are always some Linux users who bring new stuff to Linux and make it better than any other OS.
