Following a Twitter account is the equivalent of “I want to get future updates from this source”. It’s a valuable call to action that could be on many pages across the web. Twitter is uniquely positioned to own this new Follow layer, if they want it.
I see Twitter to be at its core a real time distribution system of containers with a 140 characters header. Their principal job is to build the follower/following graph and efficiently distribute those containers through this network. Their monetization should be about helping advertisers build up their following and help them get their containers in the timelines of the right people to maximize engagement.
Therefore, their most important metrics are the number of timeline views, engagement and average CPM/CPA. Where those timelines are being seen doesn’t matter much. Could be Twitter.com, their mobile app, a weekly email digest, or on a publisher site through widgets.
That’s why Twitter should offer a “Who to follow” widget for publishers. Something that you could add to your site and that would automatically suggest people to follow based on the content of the page. One of which could be of course a promoted one and publishers would get a cut.
That will give Twitter a much larger inventory to monetize but it will also give them more visibility to capture new users who want to follow brands, experts and celebrities. They could be the Follow layer of the web.
It’s about the flow baby, not the destination.