The answer is not as much as you initially think. After Google announced that it would no longer be providing search data for users who were logged in to a Google account, the (not provided) keyword started showing up (find more info on what the (not provided) keyword is here). All of a sudden we lost a decent portion of our search traffic and were left with what appears to be a rather large hole in our data. Don't get us wrong, you're still missing data, but it's nothing you can't deal with when you have BringShare on your side.

When all of the keywords that were searched by a person logged in to a Google account are lumped together, they seem incredibly significant, but the most likely scenario is that you're really just losing "slivers" from user search queries. 

To put it a different way, In all likelihood, the keywords you can no longer see are not large quantities of a few, really important keywords (which is what causes that initial panic), but are much more likely small quantities of a large variety of keywords. It makes things much more manageable if we lose one or two keywords here and there instead of losing a whole keyword or two that is driving the most traffic to your site. This isn't ideal, but you can still make grounded, logical marketing decisions that will pay off for your future.

A great article to further reference can be found here by Avinash Kaushik

BringShare is Internet marketing software that makes it incredibly simple to track your marketing. We mash all your marketing together into concise, beautiful dashboards and present it in a way for you to get the most out of your data and time. Beyond that, our automated report builder lets you build a marketing report in seconds, rather than hours.