Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Similar tools already existed on Linux like beagle (supported by novell ), meta tracker etc. However Google Desktop search is not based on any of these tools and uses its proprietary algorithms to search for files on the computer, also being 1.0 release and more stable then these products it could be preferred over tools like beagle.
Once installation of Google Desktop is complete, it automatically starts searching for files and information on your computer and stores it in it's database , the indexing take advantage of free CPU resources during time computer is idle and once entire indexing is over the Google Desktop only adds new information to its database as you use your computer .