&gt; Because as someone who analyses marketing and advertising data, I can tell you that I strongly believe they do not use GA data in this way.<p>You can choose to believe that, and I can believe that a huge company funded almost entirely by placing highly targeted adverts on third-party websites across the web has a vested interest in data collection.<p>&gt; THE WEBMASTER CAN CHOSE TO NOT SHARE IT WITH THEM.<p>Calm your tits. No one is claiming that Google hijacks other people&#x27;s websites to inject GA tracking codes.<p>The point is that saying &quot;(webmaster) chose not to share visitor IP addresses&quot; ignores a key point: GA relies on the client loading javascript from a GA domain. That means GA <i>has</i>  a client IP for the user-agent (i.e. browser) making the call. That isn&#x27;t an opinion, its just how IP networking works.<p>Edit: Because someone else in this thread referenced some very relevant parts of Google&#x27;s terms&#x2F;policies:<p>&quot;We use the information we collect from all of our services to provide, maintain, protect and improve them, to develop new ones, and to protect Google and our users. We also use this information to offer you tailored content – like giving you more relevant search results and ads.&quot;<p><a href="https:&#x2F;&#x2F;www.google.com&#x2F;intl&#x2F;en&#x2F;policies&#x2F;privacy&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.google.com&#x2F;intl&#x2F;en&#x2F;policies&#x2F;privacy&#x2F;</a><p>&quot;When you visit a website that uses our advertising products (like AdSense), social products (like the +1 button) or analytics tools (Google Analytics), your web browser automatically sends certain information to Google... When you visit websites or use apps that use Google technologies, we may use the information we receive from those websites and apps...&quot;<p><a href="https:&#x2F;&#x2F;www.google.com&#x2F;policies&#x2F;privacy&#x2F;partners&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.google.com&#x2F;policies&#x2F;privacy&#x2F;partners&#x2F;</a>