Many of your visitors probably use an ad blocker to avoid seeing annoying ads on their favorite sites. Your ads may be harmless but they are going to get caught by ad blockers anyway. Mediator for WordPress is one of many plugins you can use to detect adblockers on your site automatically.
The plugin lets you replace blocked ads with a Facebook Like button or MailChimp subscription box. You can also display a custom HTML code in place of your ads. Want to take more drastic measures? Mediator lets you block out content gradually by blurring text for the visitors with an adblocker enabled.
Mediator can detect Ghostery, Ad Muncher, Adblock Plus, and other popular solutions. It supports Google AdSense and other ad servers. You can try it for free.