Well, Matt Cutts is of the opinion that having all the sites hosted on a single IP address will not have any negative SEO effects. If cost is not a factor then you can always opt for a separate IP for every TLD but it won’t have any positive effects on SEO. Google does a good job in identifying separate websites simply by looking at country specific TLD’s.
Here is the video by Matts:
Also See:
Geolocation Targeting is Not Spam
Location Relevancy System and Relevancy Score
Types of URL Redirections
Mistakes to Avoid Using Rel=”Canonical”
Easy Seo Tips
Learn Seo – Easy Seo Tutorial
Navigation in Seo
How to Make Your Website More User Friendly
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Battle of Ranking Continues
Benefits of Seo
Seo After Panda and Penguin Update