On the 24th February Google launched AMP. Announced last October, AMP is an open source platform that aims to improve user experience of the mobile Web by reducing the possible complexity of web pages.
We at 51Degrees welcome this and think it's an important contribution to making the Web work well. 40% of people will not wait 3 seconds for a web page to load and 71% expect a mobile website to load as fast as the desktop counterpart. AMP by definition targets mobile devices and we think that while this is a useful component, web site owners will also want to target their desktop and other classes of user.
With AMP, Google are now confirming the impact and key importance of speed on Google search rankings. In order to now achieve a high ranking on mobile performance there is no other alternative than to produce separate content for mobile devices. The key point is that search rankings are not improved just by virtue of using AMP, merely that search rankings are improved by having good mobile performance - something you can already achieve with device detection.
For mobile users, AMP is not, in any case, the whole answer. While AMP pages will load fast, they do not support features that many web site owners will find useful, or essential to the purpose of their site. For example, AMP does not allow interstitial adverts, script based elements (and hence dynamic pages) and gating videos. This is where device detection comes in, if your web site requires features prohibited by AMP but you still want it to load fast then using device detection allows you to adjust the user experience and optimise delivery.
As Tim Kadlac points out; "when you take an “environment as unpredictable as the web with its broad spectrum of browsers, user settings, devices and connectivity”, - “Don't put all your eggs in one basket”. If you choose to rely solely on client side templating such as Google's AMP this is exactly what you're doing. Instead, by combining client and server side techniques you can avoid this pitfall.
AMP is a very welcome arrival on the scene, however it is not yet a substitute for fine grained control of the user experience by means of device detection.