Will you pay them? It's up to you. If you must show off numbers, we have another idea though. :)
If you have noticed strange referrals in your Google Analytics you are a victim of Analytics SPAM. Most of these visits leave a behavior pattern like normal people. Except that they are robots comming from an ever growing list of referrals.
Why is this happening?
For the money and profit as any other SPAM. People trying to sell fictional value of visits. And if you are a fan of big numbers (or your boss wants to see growth of number of visits) you may actually pay them. It's legal. Of course there are better ways to improve your traffic.
How can I get rid of them?
UPDATE: You should check the solution by Carlos Escalera that is much easier and covers most (but not all) of the issues that we have with analytics spam.
Otherwise, you cannot get rid of the bots. These visits hit your analytics as any other legal visitor. Actually, your client may be running these requests without even knowing (virus on their computer). So any kind of server side filtering may end up bad for you since you will filter the good visits as well in the end. And showing 404 page to your client who just wants to read something is by any means a bad idea.
Filter your analytics views
Luckily there is a not-so-easy solution which will take some 5 minutes of your life to prepare. Before doing anything further you may want to create a RAW view. Not really required for this but could be useful in future.
Then open the Admin tab in your Analytics account and under the View column, find Segments.
Click on +New Segment button.
Name the segment A non spammers. That A in front is intentional but not required. You can use your own name.
A Non Spammers Segment filter:
Now here comes the 3 times repeating activity:
Click on Conditions and select Source from first dropdown. Then Does not match RegEx from second dropdown.
In the textbox, enter this:
And finally at the right click on the AND button.
Now repeat this 2 times with following content of the textbox:
The final view of A Non Spammers segment:
This should be the final view. Actually not the final view because there are new spam domains popping out each day. And you should filter them as well. How?
Using the segments view
Your initial 5 minutes work is done. You can now go to reporting in your account and click on the All Sessions filtering row. At the top there should be A non spammers segment. If you have named it Z Spammers you will certainly have to scroll the list of default segments. Now you know why that A was there.
Click Apply and your statistics will drop down most probably. You may feel sad. But that is the reality. Perhaps it can help you knowing that there are people who disable cookies and are not visible in your statistics anyway. So there is 20% more people for sure in your website. :)
Is this a real final solution?
May be not. Imagine a computer which hosts a virus and runs this robot (bot). It can actually inject referral into regular requests to your website. So your client visits your website and the browser first sends a request to their server and redirects from there. What we got was a regular visit to your website through another service (SPAM domain).
If it runs this way we should not filter these visits anyway, just ignore the referral - use the filter when we are analysing the referrals. How you want to do it is up to you since it depends on your goals.
You just won a battle, not a war
This is not the end. The list of SPAM domains is growing. Each day for sure. So from now on (yes, looks like an ethernal job) you should frequently visit your Referral Traffic (Acquisition -> All Traffic -> Referrals) report in Google Analytics.
Check the results (while being in the A non spammers segment) and look for the unusual referrals. You will notice them quickly if you sort by Bounce rate or some other factors. But rarely is this list huge once you have the non spammers segment filter. It consists of social networks, search machines and some other referrals where you are present.
Now as you can see in the image, we have a new spammy referral (trafficmonetizer.org). It differs from our previous list in just 1 letter (we had trafficmonetize.org before).
What can we do? If we know some RegEx, we can play to filter both domains in that filter before. Like this:
(comma represents any character so we now cover trafficmonetize.org and trafficmonetizer.org)
You can learn Google Analytics RegEx here.
Double check with Spammers segment
In addition, we have created a Spammers segment. The same way as A non spammers, but with OR between each filter.
Why is that cool? Because you can compare the results and double check you really view the correct segment of your data. If you select both segments in your reporting, you will notice in Referrals report that regular referrals (facebook, search engines) have 0% visits from SPAM segment. That is correct.
And you will see all the spammy domains which visit your website in search of your money. Will you pay them? It's up to you. If you must show off numbers, we have another idea though. :)