Google Video (rescued by throwing a few billion at the competitor who was running away with the space), Lively (its like IMVU except without the users), Dodgeball, Wave, Google Page Creator (its like Weebly except without the users), Orkut (debatable whether one can put it in the failure column for not being FB but it certainly isn't FB), etc, etc.
But Google 'gives everything away' (with indirect monetisation), both the products that succeed and the products that fail. So in that sense this is just a list of failed products which are the byproduct of innovation at such a scale, rather than an indication of what has worked and what has not for Google in the past. Surely in this case, going up against a competitor that needs to charge, Google would be at a massive advantage (legality aside) by not having to charge?