I've had good luck with the rank of my web design site in my local market. I link to them from my site, which has proven itself to be of value for them and and I believe their links to me help me with how my site ranks. They've been spread out over several IP addresses just by chance. I was moving everything over to a new reseller account for simplicity, but they have been getting a lot of ddos attacks so I'm shopping again. I've noticed that they had a multitude of different IP addresses my sites were on, and no other reseller hosts I've looked into do. Is this of value? If all my client sites were coming from the same IP, would those incoming links have less value?
Personally, I think the IP thing has been overstated. As long as the other sites have their own independent inbounds then whatever negative score being on the same IP will bring is going to be negated by the other factors. In the large scheme of things, something as small as that is like a pebble tossed in a puddle.
I don't think Google factors the IP yet but they will in the future. The engineers will run out of algo tweaks.
Matt Cutts says he checked IPs when a site had extreme interlinking from other sites and he suspected there was a link farm. He actually did the IP check at a conference once if I recall correctly.
The only reason why the algo wouldn't consider IPs now is lack of storage space for that data. Google has been getting more storage so it's only a matter of time before IP address is part of the algo if it isn't already.
Thanks for such a straight answer, I am totally agree that at present Google doesn't bother about IP as lots of site getting backing from blogs like blog spot and word press and they have same IP and still help the site to gain link juice.