I'd like to know if this link exchange is detected and penalized by Google Site A (owner X) --> Site B (owner Y) --> Site C (owner X) All sites have different class IP. On the other hand, does Google read whois domains? Thanks in advance.
since they are a registar yes...but you can do whois protection on Site B for example... if you dont overdo this its no problem...i often boost new projects of mine this way
this is perfectly safe and your site wont be penalized. even if they are on same class IP, still you can do some interlinking as long as they are related sites and as long as there is no heavy interlinking from every single page to every single page of other sites.
I have heard good things about three way linking nothing bad and that includes nothing bad with google.