Why are my earnings dropping?

Seeing your earnings go up and down over time is common. In all likelihood, you're seeing earnings fluctuate for one of the following reasons:

• Changes in how advertisers have set up and bid for their ads
  To optimize their ad campaigns, advertisers often experiment with different keywords and ads, and also change the sites they choose to target based on past performance. Advertisers can choose to target specific sites by time of day, and may shift budgets based on their specific advertising goals. In addition, seasonality can affect bids -- for instance, retail advertisers may increase their bids during specific times of the year when their sales tend to increase. We recommend learning how the ad auction works, and how these types of changes can impact your earnings.
  
  
• The ads your users choose to click
  Since not all ads are priced the same, the ads your users choose to click will impact how much you earn. Using URL and custom channels, you can better understand which ad units your users are clicking on most frequently. This information can also help you optimize your ad placements -- to maximize your earnings, place the ad unit with the highest clickthrough rate (CTR) on a specific page first in the HTML source code. However, when applying this optimization tip, we encourage you to continue to ensure that your site’s layout offers a positive experience for your users.
  
  
• Your traffic levels
  If you’ve recently seen changes in the amount of traffic to your site, you may also notice corresponding changes in your earnings.
  
  
• Your ad targeting
  It’s important to check your pages for potential crawling problems. If we’re unable to crawl your pages, we’ll be unable to match relevant ads to your pages. Also, our crawler is less effective at deriving meaning from images or dynamic content, so we encourage publishers to include text content on their pages. In addition, after you update your site, it can take our crawler up to 48 hours to visit your pages and update your ad targeting.