Looking Up Symptoms Online? These Companies Are Tracking You
These mostly serve one-pixel GIFs; sometimes I find one-byte javascript "sources".<p>Put these in your hosts file:<p><pre><code>   127.0.0.1 aax.amazon-adsystem.com

   127.0.0.1 ad.crwdcntrl.net

   127.0.0.1 b.scorecardresearch.com

   127.0.0.1 gs.dailymail.co.uk

   127.0.0.1 gum.criteo.com

   127.0.0.1 i.dailymail.co.uk

   127.0.0.1 moat.pxl.ace.advertising.com

   127.0.0.1 pixel.mathtag.com

   127.0.0.1 pq-direct.revsci.net

   127.0.0.1 rta.dailymail.co.uk

   127.0.0.1 sync.go.sonobi.com

   127.0.0.1 t.dailymail.co.uk

   127.0.0.1 ted.dailymail.co.uk

   127.0.0.1 x.bidswitch.net

   127.0.0.1 www.google-analytics.com

   127.0.0.1 ssl.google-analytics.com

   127.0.0.1 www.hosted-pixel.com
</code></pre>
Search with <a href="https://www.duckduckgo.com/" rel="nofollow">https://www.duckduckgo.com/</a>  For extra credit use DuckDuckGo's Tor Hidden Service.