We know that having all your domain interlinked hurts Google rankings, We know that Google looks at domain registration information, Hosting, etc when figuring out where to rank a site.
Mine think is what other shared factors do you believe google looks for when ranking a site?
For EX - Shared database connections? CSS files? other "fingerprints" in the way the code is written?
yeah,I agree with you Mechanical Google looks various factors of your websites including structure of a site,content of the site,Shared database connection Css file,fingerprint in the way of coding etc.