The customer focused version of this missionis 'to help users do everything they want to do online'. Part of doing everything is providing some form of discoverability, which takes the form of linking to other products -- big traffic drivers are links on the front page to major products, and integration with search, but also relevant cross linking within the more specific verticals -- at Y! Travel, we would use flickr photos, events from upcoming, share restaurant data with local, we would have done things with yahoo calendar if it was more usable, etc.