Hi I have a web server hosting multiple domains and hence sites. This server has only one common IP address. Are the links between sites (on the common IP) effective ? Thank you
i've found that this is typically a bad idea. you want to link from different ip's. the link that this guy above me gave has some good info.
The chance of two domains sharing the same IP linking to each other not owned by the same person/organization is statistically pretty small. There's no problem having multiple domains sharing the same IP. Even if they crosslink, that's not a huge problem either. Google is pretty tolerant in that regard. But it is a negative quality signal; if you do too many other things wrong, it can be the straw that broke the camel's back.
This can be considered as a link scheme, which is against the Google webmaster quality guidelines. This issue here is Google cannot tell if the sites are all on one server OR just on the same shared hosting plan. In theory it's believe by many SEO consultants that "some" negative effect might occur. Due to the high volume of shared hosting plans it's also another theory Google doesn't give "any" negative effects to this. Common sense would tell me NOT to link my own websites together, besides the IP address being the same there are many other methods for Google to realize they are all owned by the same person. One would being using the same Google AdSense account on all the sites, or having them all registered in Google Webmasters Central. I would spend my time making rich unique quality content so I could build "natural" backlinks, why else would someone want to link to your site if there is nothing "useful" on it? Think about it!