The UTM is the Google Analytics Traffic Monitor - proprietary Google Analytics Tracking Code (urchin.js), which is installed on a web page for the purpose of collecting Customer Data, whereby unique visitors can be accurately tracked using a combination of server and client-side technology including cookies.
# [Google Inc]
127.0.0.1 www.google-analytics.com
How this works: Google Analytics downloads a small javascript urchin.js (Google Analytics Urchin Module) on the client's computer which reports the all the tracking and analyzing data about the visitor back to Google. By adding the above line, we have effectively blocked our browser from downloading the urchin.js file.
If you don't like changing the the hosts file manually, download a free Hosts File Manager utility to manage the hosts file for you.
If you are using Firefox, CustomizeGoogle extension lets you block all Google Analytics cookies, on any website. Using this feature makes you more anonymous. But your visit on a single webpage can still be logged. This way, both Google and the owner of the website knows that someone visited a webpage, but it's difficult to track all pages you're visiting.