Selected answers from the Dumb SEO Questions G+ community.
Razvan Alexa: the interlinking should be done based on relevancy...relating articles referring to the silo as a resource, the silo referring to the related articles in order to read in more depth about particular subjects
Tom Gooden: Because of a nav, footer links, etc, interlinking looks more like the picture below. However, contextual interlinking within the body is a different story.
Alan Bleiweiss: If you don`t link downward based on relevance , not enough value will be passed down the path.
If you don`t provide breadcrumb navigation or section specific sidebar navigation to support that, you aren`t reinforcing topical organization.
Beyond that, linking within content needs to exist when that also reinforces strong relevant content relationships.
Blake Aylott: I just started doing this to a new client`s site in January and the amount of impressions they are getting is going way up. All I did was link together all of the content together naturally. I just linked to relevant internal content where it made sense to.