So, how do search engines know if one person owns all of the sites that are cross-linked? The struc-
ture of a set of cross-linked sites is the first clue. A group of sites that have naturally occurring links
might look more like the diagram shown in Figure 13-2.
Other factors that may help a search engine decide that all the sites are owned by the same person
are the IP address of the site and the WHOIS information. The IP address is unique to each different
web site. Two sites that are owned by the same company are usually hosted on the same server, and
so the IP address of those sites would be the same. And WHOIS information is the record of domain
ownership. You’re required to provide this information when you purchase a web site.
When sites owned by the same company or individual are cross-linked, search engines look very
closely to ensure that the sites are relevant to each other. If they are, then there are no issues with
the cross-linking. For sites that are not related, however, search engines look down upon the prac-
tice of cross-linking and your site (or sites) could be penalized for search engine spamming.
Natural linking between web sites is not as circular or organized as cross-linking schemes are.
Understanding the Role of Links and Linking
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