When you add your domain to Monitor Backlinks, you are prompted to add the keywords you want to monitor for your domain.
The tool will recommend keyword suggestions that you may wish to monitor based on your Google Analytics data.
You may or may not already be ranking for the suggested keywords in Google.
There’s a good chance that you are already driving traffic from the suggested keywords, so it's a good idea to track them.
You can remove monitored keywords at any time if you need to.