Pivots are gut wrenching. The more eyes there are on the company, the tougher they are. Therefore, public-company pivots are usually the most gut wrenching. Many public companies of the past ceased to stay public because their leaders couldn't face the pivot (change is a bitch - who moved my cheese?!), their business radically declined, and they eventually got delisted from NASDAQ or the NYSE.
Sometimes startups we meet with (I've personally seen over 1,000 pitches in the last two years) talk about their network effect in a hopeful way. But most of the time it is just that - hope, and hope is not a strategy. But Bazaarvoice actually has a working network effect that benefits all participants: retailers, brands that sell through those retailers, consumers that shop at those brands and retailers, and Bazaarvoice and some of its partners. In other words, the more participants that are on the Bazaarvoice network, the great the effect of that network for the benefit of all. I wrote about this in detail in my first annual shareholders letter after Bazaarvoice became a public company.