We went to university together http://elephanttube.in.net/ elephanttube.com When Twitter was in user acquisition and retention mode, it built out a secondary service though email notifications. These notifications were intended to remind you that Twitter exists, and to follow more people. Now that Twitter is in IPO mode — live event and advertising mode — its goals have changed. What Twitter could create, and seems to be creating, is a live push notification infrastructure, centered around mobile devices, designed to bring Twitter’s users where they need to be, right when Twitter needs them.