As he mentions in passing, marketplaces seem to be a good solution to both of these options. Once you reach a critical mass you potentially have a large viral e

As he mentions in passing, marketplaces seem to be a good solution to both of these options. Once you reach a critical mass you potentially have a large viral effect, user lock-in, and a high lifetime value as users get used to purchasing on a regular basis. The only trick is conquering that chicken-and-egg issue.