As the airlines have discovered, and the wireless companies soon will, locking in customers is impossible over the long run. Some competitor will figure out how to spring them.

Voice not only offers a way to monitor customer satisfaction, but also provides a value in and of itself. I don't expect my every whim to be answered, but I do want to be heard. Giving customers a voice is a way to recognize their individuality and to show respect.

HBR Blogs: Yahoo, Tumblr, and the Loyalty Factor, 2013-May-5 by Ben Gomes-Casseres

Against the backdrop of civil strife and war in the late 1960s, Hirschman wrote that when faced with declining institutions, consumers have two choices: Exit and go elsewhere with their support or dollars, or use the power of voice to generate change from within. These two choices are mediated, he explains, by members’ loyalty to the institution. Loyalty makes people more likely to stay and work for change from inside. But loyalty is also a product of how effective a consumer’s voice is likely to be; it does not stem from feeling locked-in or having no possibility of exit.

…can Yahoo count on Tumblr users staying on? That is probably how the investment bankers framed it — as a question of switching costs, lock-in, network externalities, and the like. Where are these users to go? There is no equivalent forum of this type, richness, and network size (at least not yet). It would seem that the 18-24 year-old demographic that Yahoo is pining for does not have an easy exit choice.

If the new owners indeed think that this community has nowhere to go, they will kill Tumblr, and possibly Yahoo too. As Hirschman explained, in an organization where entry is easy, exit may also be easy.