Dedicated IPs Fact and Fiction
 

How well do dedicated IPs improve your search engine results? What type of sites should have a dedicated IP? I mean if I build a few different TGP sites should I use a dedicated IP for all of them? If I have a blog can it share an IP with a TGP? I know I CAN but should I?

There has been an approach by many SEO people to suggest using a dedicated IP. Generally they are only needed if you are going to use an SSL certificate or need it for you network connection to the internet for example.

As far as SEO goes though, the domain name is going to define your site, not the IP address. The only time it matters is if domains on the SAME IP are linking to each other. These links may be ignored or even get you booted off Google if it appears you are using a number of sites you own to boost your search rankings.

Raunchy laid it out there pretty damn good. Dedicated IP's are normally used for SSL...Actually, they are required for SSL. But, if you're using dedicated IP's for SEO purposes then make sure they have different C classes.

You should also make note that idiotic SEO campaigns like this are one of the main reasons for the relatively fast exhaustion of ipv4 address space

http://en.wikipedia.org/wiki/IPv4_address_exhaustion

The short story:
Not dedicated IP = problems with SEO, problems with sending emails (especially if others do dirty stuff on that IP)
Dedicated IP = it all depends on you if an IP will stay reputable or not.

2 sites from same ip shouldnt target the same keyword

totally agree