So then you're a single-tasker?

Login to gmail, check messages, reply to messages, logout. Go see what's happening on twitter... login, scroll through timeline, send some tweets, logout. Go over to salesforce, update some customer records, look at chatter, logout. Jump over to kill some time on HN... login, look at replies to comments/discussions...

You get the picture. Nice idea in theory but immensely impractical for almost any standard user.