No Authentication Vs. Last Authentication in a Profile Merge Rule

[glennb29356951]

Hello, 

I've read all the documentation and am wondering the true difference between a segment created with a profile merge rule No Auth and Adobe Co-op device options and Last Auth and Adobe Co-op device options. 

If there is no authentication is the match done in the co-op 100% probablistic? 

Please advise. Thanks. Glenn

[caseyo84500701]

More of an assumption than an exact answer since I don't work for Adobe, but I'd assume it's still a blend of probabilistic and deterministic. I say that because the UUID is persistent for each device across all AAM client domains, so even though there may not be an authentication event on your website, it might be linked elsewhere.