Am I able to run OS X 10.11 on my Mac or not? I have a Mac. It is running Mac OS X 10.6.8. It is ten years old, came out in 2006.  I go to the App Store.  The listing for OS X 10.11 claims it is "compatible with 10.6.8", but when I "get" (click on the Get button) the update, it comes up with a message that says "...cannot be installed on this computer."

What am I doing wrong?
Checking everymac none of the Macs listed is eligible to run 10.11 El Capitan.

The latest supported system for Xeon/Core 2 Duo processor equipped Macs from the year 2006 is 10.7.5 and 10.6.8 for Core Duo.

Being "compatible with 10.6.8" means that any Mac running 10.6.8 and supporting 10.11 can be upgraded directly. Macs supporting El Capitan either contain Core 2 Duo (2007-2010), i3/5/7 or Xeon (2008-) processors.