A workflow that requires reviewers to acknowledge having viewed the page.
A routing workflow defines the reviewers who are required to view a page. By clicking "approve" a reviewer in a routing workflow has acknowledged that she has read/viewed the page.
Routing workflows do not control viewing or editing permissions and do not control draft or published states. Routing workflows are akin to the "routing envelopes" of yore, which required individuals to sign their name as acknowledgment of having viewed the circulating document.