I have heard that sites sharing an IP address will not rank as high a sites that don’t. I have no proof to back this up but most sites on the internet share an IP and I have seen sites like this have a high pagerank.
If there is any truth to this I would have to believe that maybe sites linking to each other with same IP may not be given credit for that backlink because they are on the same server and the search engines might think that they are run by the same webmaster which they usually will be.
I am relying on comments to get this one straightened out.
August 29th, 2007 at 9:55 am I don't believe that ip sharing would influence ranking, why would shared sites have less important content than sites which span multiple ip's or dominate one address. It's not even possible to give every website it's own address! Lot's of rumors go around about ranking, and this is one of them that has the least funding if you ask me.