JS_Harris - 2:15 am on Jul 18, 2013 (gmt 0)
You would have 20 domains because you got tired of working on one only to see it kicked to page 5 with every new Google update. "maybe there is something wrong with this site?" hmmm, ok, frustrated I think I'll start a new site and work on that for a change.
As for the video - I have a pair of seasonal sites and within 3 days of interlinking them I lost significant traffic(4 years ago) that has never returned. It made sense to interlink them, it was ethical, but that didn't matter.
As for the video - I found it interesting that Matt was comfortable at about 10 interlinked domains in the footer but got iffy at 20. This, to me, suggests some interlinking even from the footer will not cause an instant penalty per say(but may have, 4 years ago).