I heard that if you have all sites with same IP and make them link to each other, Google will ban them because they assume you try to increase your link popularity. Google don't like webmaster increase their link popularity and Page Rank with their own website that has same IP address.

Is that true? I post in many forums, but still don't have any answer.

The only time you get banned is by doing something to fool the search engines.

If the links are there because they could be useful to vistors then they won't be a problem.

I think it's just if you're doing something like creating a bunch of no-content spam pages and then linking them to each other in just so that you can increase your page rank. But I think the main reason you would get banned in that case is just because you're spamming the search engine, not because you're linking between them.

Plus, google won't ban just because they are on the same IP, there a lots of hosting companies which put hundreds of websites on the same IP and some of them are most likely linking to each other.

That's my thoughts on it...

i have been interlinking sites with same ip with no problem, in fact it seems to help quite a lot. I try to link only related sites from index page and i wouldnt do triangle linking on sites with the same IP.

I've never actually talked to anyone who has been banned for this, it appears to be a bit of a myth. I think the people who get banned are the ones who create hundreds of doorway pages, use cloaking or keyword stuffing on their sites.