I'm interested in starting several sites that are "borderline related" to my main site. They're more or less about the same topic, but will cover a lot of side issues not covered on the main site. Where I can do so relevantly, I'll be linking to the applicable pages on my main site.
The question I have is, will Google (or the other SE's) penalize me if I'm listed on as the domain owner for each domain? I've heard some rumors that they don't like it if a single person owns too many sites on the same topic and that somehow they can count domain and site ownership into account in their algorithm. It doesn't make sense to me, but I wanted to make sure before proceeding with this plan.
Additionally, to save money and generally make my life simpler, I intended to host these smaller sites on a single multi-domain hosting plan. Obviously all the sites will share a single IP address. There's another area I've heard of penalties; too many related sites on too few IP's. That seems more reasonable to me, but then I've heard everything from "it makes a lot of difference" to "it doesn't make any difference at all."