About AdSense achievement cards
If you see an “AdSense achievement” card on your Home page, it means that you’ve just passed a major milestone in your account’s history. Congratulations!
AdSense achievements are a fun way to celebrate important events in your AdSense career, such as reaching a total of 100,000 ad impressions, or serving your 1,000th ad impression on tablet/mobile, etc. Whenever you receive a card it’ll be shown on your Home page for a limited time before it expires automatically.