Matt Cutts put out a good video today answer the question from Kenichi Suzuki of Tokyo, Japan when he asks, “Suppose I have a site that covers fishing overall (A) & I make another fishing site that solely focuses on lure fishing (B). Does linking to A from B violate guidelines? I’ll make sure both have high quality content & I disclose that they’re both owned by me.”
Essentially the answer is what you’d expect, if there are only as many sites as you can count on one had, and if they are good quality and thematically related, then it makes sense. Any more than that and it starts to look like a link network.
I know I’m going to use this video to reinforce to folks what I’d said before but without Matt’s voice behind it.
For those who haven’t seen it yet, here’s the full video (a whopping 2 min 24 sec):