Server-Side Mobile Web Detection Used by 82% of Alexa Top 100 Sites

By Ronan Cremin
Ronan Cremin

About 82% of the Alexa 100 top sites use some form of server-side mobile device detection to serve content on their main website entry point. As you descend from the top 10 to the top 25 and top 100 sites the percentage of sites using server-side detection falls from 100% to 96% to 82%. This is an interesting fact given that all the recent discussion in the blogosphere is of responsive design using client-side techniques such as media queries. You can read more about these techniques in our article describing current mobile adaptation techniques.

How exactly did I measure this? I took five devices and visited the main entry points for the latest Alexa Top Global Sites list. I compared the size of the returned HTML document for each of the devices in question to see if server-side redirection and/or adaptation was being used. To avoid having to actually view the resulting page from each device I used the page byte size as a proxy measurement: if different user-agent strings resulted in significantly different returned HTML byte size for the same URL, I count this as server-side device detection at work. Where known, I used the full set of HTTP headers for each device in addition to the correct user-agent string.

Server-Side Mobile Web Adaptation
Top 10 SitesTop 25 SitesTop 100 Sites
Extensive (greater than 3 versions)80%88%74%
Any adaptation at all100%96%82%

Google is the star performer, fine-tuning all of its properties in all territories. The most notable non-adapting sites in the top 25 are Apple and Craigslist (to be fair to Craigslist their site is quite efficient thanks to its spare use of images).

In conclusion, while the blogosphere is full of lively debate about new methods of achieving mobile adaptation using JavaScript, progressive enhancement and media queries, the data show that the giants in the web arena are using server-side device detection techniques to achieve this goal. The techniques are not mutually exclusive of course, but pragmatism suggests that the method used by the big brands is at least worth a look.

Testing Notes

Mobile Devices Used

By Ronan Cremin, Director of Engineering at Afilias Mobile & Web Technology Division. Mr. Cremin leads R&D activities for mobile and web Including the award-winning goMobi and DeviceAtlas products.

Related topics: Mobile Internet, Web


Detection (& Redirection) Matters! Florante Valdez  –  Jan 11, 2012 9:28 PM PDT

Great article. At Handset Detection we make this easy for the smaller players as well.