Google analytics is, for many businesses now a days, an important tool to measure not just the traffic to your website, but how efficient is the SEO (Search Engine Optimization) or SMO (Social Media Optimization) implemented in your website and Social Networks. It shows you not only the organic searches statistics but detail on what keywords were used, what technology, demographics etc.
But what happens when you go to your account in Google analytics and you want to see the keywords used to find your website on the organic searches and you find that there are hundreds of searches done on "(not provided)", what does that mean? And why do I have so many searches with that keyword?
To begin with, if you are logged into your google account and you do a search on http://www.google.com, as soon as you press "search" the URL of the results will begin with https://www.google.com/.... not http:// but https://
Why? Because your search is encrypted with SSL, or Secure-Socket Layers, which is the same type of encryption you see when you enter your credit card during an online purchase. To read more about this you can go to: http://googleblog.blogspot.co.uk/2011/10/making-search-more-secure.html
Apart from many other things, this means that the keywords you use in your search will not be shared in tools like Google analytics due to the encryption and instead you will have "(not provided)"
Now if you are the type of person or business that keeps a close eye to the results generated by SEO and SMO to be able to measure ROI then you will need to make use of other tools to complement Google analytics, like Google Webmaster Tools, Alexa.com and many others available for free.
And for the ones that are not tracking yet the keywords, I will like to say that ranking on Google is a phrase used everywhere, people say "I want my business to rank on Google" but what keyword do you rank with or what keyword would you like to rank with or even better what keyword will be the easiest and most profitable one to rank with which is the KEY to have not just high traffic but good conversion?