The crowded blog search space may soon contract now that Google has debuted its Blog Search service. Like competing services Technorati, Feedster, Blogpulse, and Ice Rocket, the database relies on site notification rather than crawling. Like Feedster and Ice Rocket, Google's index uses RSS feeds as its data source. Google's entry is still beta quality but in some informal testing, I found it had picked up a number of blogs which its competitors had ignored. Things are about to get even more interesting as blog searching becomes increasingly sophisticated. I wonder which Google competitor will bite the dust first?