We all know that building a link farm in order to boost your site's PR can get you penalized but I have heard that Google also checks Whois info, and even if you linked sites that are not from the same C block IP the same Whois can be considered as link farming. Is there any truth to it?

Unless you're heavily interlinking with each other I think you should not worry about this.

I don't, but it's just too much variables in the game of SEO. It drives me crazy. I think that a normal person can't track all of them. It makes you forget about what is your content in the first place.

I had a "almost new client" who inquired about our company letting him do this.

And I am really surprised at the number of people out there who think that one good way to get ahead is of course to cheap, you know, since the hard route is never worth the reward in the end.

With more than 5,000 domain registrations with our technical contact information listed on them and links back to our company with the standard "domain registration provided by" text, I can tell you that as of yet we haven't had any issues with google listing that information and causing problems for our site.

Could you imagine Network Solutions or GoDaddy with their millions of domains and information listed and google penalizing them for linking back to themselves?

I wouldn't believe the hype (if there is hype - never heard any).

I highly doubt Google penalizes anyone related to their WHOIS data. I think their main focus is relevancy to the search query.

Class-C Addessing has been an obsolete concept for over 5 years and CIDR range is irrelevant to Goooogle

Are you saying that having multiple sites in different class-c's have no impact on SEO?

It would be impossible to have sites in "class-c's" as they no longer exist.

Search Engine's have understood shared hosting for longer than most hosts have existed - IP address is irrelevant in the respect of incoming links - its a "snake oil" solution ...

This has been confirmed over and over again by the SE authors, yet this "persistent myth" prevails.

* Content is the most important thing

* Valid HTML and use of correct/appropriate tags we've proven makes a difference

* Fixing internal links does affect positioning - run a test on your sites

* Response Speed matters (we've seen clients jump up 3 pages in google simply because we peer with G and the response times are therefore much better)

* Location of server (IP to Geo location) matters (several countrywise SE's will only list sites on an IP in that country)

* Incoming links and the Anchor text used, related blog posts, and so on all have an impact (affect the overall results) where all other things are more-or-less equal, but are secondary to the above.

Take it easy. Whoc is is whois but SEO is SEO and they are bot conneted with each other in any way