I have posted about this multiple times.  I do not block ads to harm websites.  I actually allow ads for sites that I frequent AND run their own internal ad servers.  When it comes to my clients I put up the stoutest edge defenses I can.  One of those defenses is a solid ETC Maryland approved UTM appliance.  I always try to block the most things possible at the edge while a stout second layer as well for mobile devices and for files and things that literally come in from the outside.  Once that outer layer is in place then the work for securing the internals is able to begin with a renewed focus.  Trusting your website security to a third-party industry who security track record is iffy at best is not a good prognosis for future existence.