In two previous posts, we outlined the extent to which iOS 6 defaulting to Google secure search led to organic searches being incorrectly attributed as direct visits, and we offered some guidance on how to estimate the impact for your site as Apple's latest mobile operating system continued to make gains in overall traffic share. The problem has been that Google secure search on mobile devices fails to pass a referring URL, and without that referrer, analytics packages cannot determine the traffic source. With paid search, however, advertisers typically employ tracking mechanisms that are not dependent on the referrer and we can see how often Google paid search clicks do not pass along the referring URL. For iOS 6 devices, we have observed that typically 70-80% of Google paid search clicks have not been passing a referrer. Applying that knowledge to organic search data has allowed advertisers to estimate their true volume of organic search visits with strong accuracy. But, paid search data on missing referrers is no longer a good proxy for organic search.
What Happened on May 8th?Missing referrer rates for iOS 6 had been pretty stable since the operating system was released in September, 2012: No surprises there. Referrers are passed or not passed based on how the user conducts their search (Safari search bar searches do not pass a referrer, but a user search directly on http://www.google.com would pass one) and this behavior would have to change dramatically for these rates to shift much on their own. Beginning on May 8th though, we saw a sharp decline in Google AdWords clicks from iOS 6 that did not pass a referrer, but total iOS 6 click volume remained steady: This transition period lasted through May 9th, and since then, missing referrer rates have been stable at around 40%. The timing doesn't appear to fit with any changes that Apple may have made. iOS version 6.14 was released on May 2nd, but all versions of iOS 6 show a similar trend. Google did release Google Now for iOS on April, 29th and there's a bit of a wobble in the numbers above around that point, but nothing close to the later drop. It appears Google must have made some other change on May 8th to produce these results. I should note that in the limited tests I've conducted, I have not been able to generate a referrer in an unexpected fashion.
Organic Search Not AffectedSeeing more referrers gives us greater insight into the raw paid search queries that trigger our keywords, but referrer information is much more critical to the organic search side. Unfortunately, whatever has produced the decline in missing referrers for paid does not appear to be impacting organic search. With iOS 6 generating nearly 90% of iOS visits and iOS generating around 20% of all site visits, a sharp increase in iOS 6 referrers being passed should lead to an obvious jump in organic's traffic share as it gains back some of the traffic that is incorrectly being labeled as direct. This hasn't happened: If the percentage of missing referrers had dropped for organic searches at the rates observed for paid searches, we would expect iOS share of organic to increase by roughly 3-6%. That would still trail its share of all site and direct visits -- 40% of iOS 6 referrers are still not passed for paid -- but it would be a much more accurate view of organic search traffic in our analytics packages. Since we have not seen any real movement in organic traffic share, it should be safe to assume that secure organic searches from iOS 6 devices are not passing referrers at rates similar to what we have seen all along, despite what may be happening on the paid side.
A First Step?In my original post on the iOS 6 issue last October, I concluded with a bit of speculation as to what we may see over the next year:
Within a year, not only will we expect iOS 6 to be on about 90% of iOS devices – as we saw with iOS 5 before the newer version was released — we should expect the entire iOS pie to be larger as the growth of mobile browsing continues. At this time next year we could be seeing somewhere on the order of 13-15% of organic search traffic vanishing into the direct visit bucket. That is, unless Google decides to bring its mobile secure search in line with desktop and begin passing a referrer stripped of the search query.... Personally, I’d be surprised if a change isn’t rolled out before the next iPhone is.The first part has proven to pretty accurate, but it remains to be seen whether Google will employ a scheme for mobile secure search that works similarly to secure desktop searches where a referrer is passed for organic, but the query comes across as (not provided). It might just be wishful thinking, but maybe what we are seeing is a first step towards that end. Update: To clarify, as Danny Sullivan pointed out in a post yesterday a big issue here seems to be mobile Safari not handling the meta referrer specification properly. In theory, we should at least be seeing the "bare Google host names" like www.google.com as the referrers for iOS 6 secure organic searches, based on what Google is doing. So, the responsibility here really lies on Apple, but Google could still employ a fix.
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