Running a random test over all visitors to dslreports.com shows that over 26% of visitors use a browser Adblock extension to remove ads. This is the percentage measured from the population who do not block most scripts, including google analytics, by default (by using NoScript or Ghostery etc). It is likely the uncounted "dark matter" visitors almost certainly also block ads.

Among just Desktop Chrome and Firefox users, the percentage of Adblock in use is higher - almost 50%, leaving Internet Explorer Safari and Mobile to pull the balance back to 26% overall.

Wondering why the Facebook "Like" button count is the same as the "Share" button count? it is because the count in a "Like" button:

is actually Likes+Shares+Comments

For example the Like or Share button for google.com is broken down as follows:

https://api.facebook.com/restserver.php?method=links.getStats&urls=http://www.google.com
 

Take aways:

The "Like" count is not likes, it is engagement.

The "Share" button count is not shares, it is the same engagement number.

XHR2 - Browser XMLHttpRequest() is a boon and also a curse. Here are just a few of the ways you can be tripped up.

1.