The keyword not provided issue has caused serious issues (some would say damage) for search engine optimization professionals and those responsible for performance analytics, particuarly when it comes to keyword level reporting. And the situation is only going to get worse.
When users are signed in to Google and use the Chrome address bar (the "omnibox") to conduct a query today, Chrome sends those searches over SSL - that's why many have seen their KNP data increasing over the past six months. Now however, or at least starting with Chrome 25 (currently in the Dev and Beta channels), Google will do the same thing for users who are not signed into Google. That means that searches from Chrome address bar will be unavailable (i.e. invisible) - that's right, keyword not provided.
Google introduced Encrypted Search in May 2010 and made encryption the default for signed-in users starting in October 2011. While it may be a good thing for end-users - faster speeds and all, it's causing quite a bit of disruption in the search marketing landscape.
- The Extent of Keyword Not Provided & Some Practical Solutions