Referral Spam occurs when bots visit your website, and these visits are then recorded in Google Analytics with the spammed URL attached.


These URLS could show up as:


semalt.com

social-buttons.com

etc.


These crawlers generally do not make your site unstable. Therefore it is not necessary to block them via Savvii.


Using a filter in Google Analytics usually suffices when trying to prevent referral spam. In the article below you will find many different ways to accomplish this.


http://www.analyticsedge.com/2014/12/removing-referral-spam-google-analytics/


Unfortunately, you will be fighting an endless war against spammers since they will continuously change their domains.