很好的科普文章，帮大家温习了一遍storage system、database的基础知识。
这个问题跟“已经2015年了，为什么人们还在使用email”类似。短信是很及时的通知手段，90%的短信在几分钟内能被读到；不用上网也能发短信；A2P（Application-to-person），短信连上各种api；是一种身份验证机制（发送验证码）。
与手机和平板电脑比，手表上app的使用会很频繁，但每次互动的时间不长，所以不同平台上app的设计不光是屏幕大小的不同。
Today with the Apple Watch, the same type of awareness is important for designers – users will likely interact with smart watches in shorter bursts, but more frequently, than they will with their phone or tablet. So, when designing for phone, tablet and watch, it’s not just the screen size that varies, but how the user intends to use the device, the amount of time they’ll spend using, and where they’ll interact with it. All of these factors have implications for the design for apps that run across these devices.
Google前工程师介绍他们在公司里自发组织的兴趣小组，利用零散时间改进代码、改善工程文化、做工具等。总之，就是做一些“重要但不急迫”的事情。