A little known feature of the latest iOS 5 software for the iPhone is that it disables cookies by default. I wasn’t aware of this until yesterday when I tried to book a hotel and was trying to browse three of the largest travel websites – Premier Inn, Late Rooms and Travelodge and none of them were working.
All these sites detect your user agent, set a cookie and then display the mobile version of the site. In iOS 5 this results in a redirect loop which I only fixed by enabling cookies in the settings, something that most users wouldn’t know they needed to do.
I’m guessing that there are thousands of sites out there that suddenly are seeing very low conversion rates from iOS 5 users. Certainly any sites that rely on cookies need to figure out a new way of working with iPhones.
This just goes to show the importance of a weekly reporting system that shows traffic and conversion rates for different browsers & operating systems.
There are loads of threads on various forums from users saying they can’t login to services after the iOS 5 update.