Noah Brier, guest posting on Ad News:
It represented more than just that, though, it was also an acknowledgement of the current state of content on the web: the move to "stock and flow," a metaphor coined by Robin Sloan, formerly of Twitter (and the blog Snarkmarket). Stock, Sloan explained, "… is the durable stuff. It's the content you produce that's as interesting in two months (or two years) as it is today. It's what people discover via search. It's what spreads slowly but surely, building fans over time." Flow, on the other hand, "… is the feed. It's the posts and the tweets. It's the stream of daily and sub-daily updates that remind people that you exist."