WTF is "?ref=s0d.org" ?

[buRnt]

I was checking the "More results from www.example.com" link in Google and the last result for one of my sites had "?ref=s0d.org" on the end of the URL.

example of what it looked like...
www.example.com/?ref=s0d.org

When i click the result it goes to the front page of my site. WTF is this shit?

 

[Bofu2U]

Do you have an affiliate program? heh.

 

[MyOwnDemon]

It looks to me like it's a referral. Someone is sending you traffic and then tacking their ID on the end. Looks like spam. Do you have any link exchanges? Do you run any referrer scripts?

 

[buRnt]

I'm not running any affiliate programs or referrer scripts.
They look like this (except for my site)...