The road less traveled by

High Scalability談發表的Google+開發工具介紹時，提到為什麼Google+ API推出速度緩慢的猜測：

So the approach is: make the UI first, make it fast, and then wrap an API around whatever evolved. A controversial methodology, but given the imperative for making a responsive UI, it makes sense.

However good this approach is for creating fast UIs, it's death for feature development and fast responsive innovation. With an API you can develop in parallel and release stuff faster and iterate faster.