There are various Analytics and Search Engine Optimization services that will load up your analytic systems with referral traffic. The problem is that they aren’t real referral traffic and bloat your data. What these typically are really, is a crawler but doesn’t act like a standard crawler. So you get overwhelmed with referral data that isn’t of any value.
If you using Google Analytics you can remove this traffic with filters.
Here is an example filter I use on my website as I don’t find value of the data that gets flooded into my analytics account.