Ep # 83

Source: Internal Links Guide

Where does the number 100 come from?

Matt Cutts in 2009 mentioned 100 in his blog post

Starcom’s Jason McGovern is that it’s one of the few methods site owners can use to tell Google (and visitors) that a particular page of content is important.

Also, as Jason points out:

From a strategic perspective, it helps site owners bridge the ‘authority gap’ between their most link worthy content and their most profitable content.