Welcome BigJimbo!
Let me tackle your various comments separately:
I understand that putting a site out there with nothing but links is a no-no. And I understand that sites that have little or no content but plenty of links (like doorway pages) can get you into trouble.
No, actually, this isn't true. Directories are generally just nothing but links, and there's nothing wrong with them. Pages with links are fine.
Pages with links that are put up just to direct traffic to one of more of your own sites, are what can be a problem.
But what if you have a dozen different domains that each have plenty of unique content and a unique product and a unique ordering process?
Doesn't sound like there's anything wrong with having that. Sounds like a good idea. But what's this got to do with pages of links?
In an effort to maximize my link popularity should I put links in each domain from my other domains? Or will the major SEs penalize me? All my sites are with the same host and have IPs from the same number blocks.
Are the sites related? Do they have anything to do with each other? Will someone interested in one of your product lines be in your target market for one of your other product lines?
If the answer to these questions are yes, then it of course would be a good idea to link to them so that your visitors can find them.
If the answer is no, then it wouldn't make sense to link them. You don't want to link them just because it would be good for the search engines. That's a good way to get yourself into possible trouble. Most likely, it would not be a problem, but it could eventually catch up with you. Especially if those were the ONLY links you had.
Make sure you have links that exist outside of your own little network of sites. This will help you to not run afoul of any rules.
It doesn't matter if your sites are all hosted on the same server because you don't have anything to hide. The only time it matters that they're all on the same server is if you're trying to trick the engines into thinking that someone else owns the sites, not the same person. Since you're not going to do anything tricky or sneaky, you have nothing to hide. I assume you will make it obvious that you own all the sites. That's perfectly fine and the exact right thing to do.
Good luck!
Jill
