Google's pattern of launching social networking products that fail to dislodge Facebook had, by late 2010, become a reliable feature of the technology industry's competitive landscape. Each launch was accompanied by genuine product innovation and genuine strategic reasoning; each failure illuminated something about the nature of social network lock-in that Google kept learning and apparently kept forgetting.

Hotpot was a local recommendation service that asked users to rate businesses — restaurants, shops, services — and used those ratings to generate personalized recommendations while allowing friends to see each other's reviews. The concept was sound: local business recommendations from people you know are inherently more valuable than aggregate reviews from strangers, and Google had the mapping infrastructure and search traffic to give the product a significant distribution advantage.

What Hotpot could not overcome was the problem that all Google social products have confronted: Google knew where its users were going and what they were searching for, but it did not have meaningful data about who those users' friends were or what those friends valued. Facebook had exactly that data. A restaurant recommendation from someone you follow on Facebook, or a friend whose taste you trust, carries information that a Google-generated recommendation based on demographic similarity cannot replicate.

The product was eventually folded into Google+ when that platform launched in 2011 with considerably more ambition and resources, which was itself eventually folded into Google Maps when Google+ failed to achieve social network scale. The local review functionality that Hotpot pioneered survived; the social graph that would have made it truly useful never materialized.

The lesson Google appeared unable to internalize was that social networks derive their value from historical deposits of social data that cannot be replicated from scratch by a superior product. You cannot build Facebook by building something better than Facebook and waiting for people to switch.