Semalt.com is a company that sends robots to websites as a keyword ranking program that causes a 100% bounce rate and no actual visitors. I’m actually quite surprised they aren’t banned from Google already.
Filtering Semalt is an option, but you will only be filtering future data and not past. You can go to the source and requesting removal entirely, but people in our industry are questioning whether that works or not. Here is an area on the semalt.com website where you can request your website be removed: https://semalt.com/project_crawler.php.
I hope Google follows up by cracking down on Semalt and other bots that are skewing our data. We will keep you posted on the effectiveness of the removal requests from our tests.