Myslím že důvod, proč byla služba stažena, je celkem jasně vysvětlen na stránce Google Labs FAQ (http://labs.google.com/faq.html):
What happened to that cool thing I was playing around with last week?
The prototypes on Google Labs are meant to be low maintenance experiments. If one disappears it may be because no one was interested enough to use it, it wasn't stable enough for users to try it out, or it was so wildly successful that heavy usage brought the server to its knees. While that particular application may not reappear, there should be something equally interesting to replace it shortly.