<p>If you see a post that has been edited, if you click on the "Edited [Date]" link you will see a list of post revisions. I'll use your question <a href="http://serverfault.com/questions/342172/what-is-the-microsoft-loopback-adapter-used-for">here</a> as an example.</p>

<p>If you click on the link as shown in the red box:
<img src="https://i.sstatic.net/MDwWS.png" alt="enter image description here"></p>

<p>You can see (in red) what was taken out and (in green) what was added.
<img src="https://i.sstatic.net/QKxnj.png" alt="enter image description here"></p>

<p>For more info, have a look at <a href="http://meta.stackexchange.com/a/21789/155320">this</a> FaQ entry, "How Does Editing Work?"</p>