Recently Google Analytics added “Bot Filtering” to “Exclude all hits from known bots and spiders”
Find this checkbox on the View Admin page under “View Settings”.
This will screen out some chaff that has been skewing your stats Analytics.
Cleaning up your Sessions & User counts going forward to exclude various robots & spiders.
You may (may not) be surprised to see that 10% or more of your traffic screened.
Don’t panic over a drop in sessions or users after putting on this filter.
(Remember they weren’t real prospects for your business)
What is important, is that behaviour statistics like time on site, bounce, pages per visit, repeat visits, visit paths, will be cleaner.
Let’s face it, you want to base your decisions on the behaviour of people on your site, not machines.
Better data, better decisions.
If you are having issues with others, particularly errant referral entries, such as semalt*com.
You may need to add a specific filter. Great instructions here. http://www.hallaminternet.com/2014/remove-semalt-google-analytics/ . If those instructions do not work for you, try using the regex “/.semalt/.com”
Hopefully GA will add these guys to their known bots list soon.