Grammarly does not control the ads showing in your browser. However, as your browser collects your browsing information while you're surfing the web, it might identify your search history as pointing to your possible interest in our services, showing you our advertisements as a result. You can learn more about web advertising here: http://computer.howstuffworks.com/advertiser-custom-ads2.htm
You can also opt out of interest-based targeting provided by participating ad servers through the Digital Advertising Alliance (http://youradchoices.com).
If you normally use Google as your main search engine, you can follow the steps in this article to block advertisements: https://support.google.com/ads/answer/2662850?hl=en