Currently, clicking the date of a Flow post shows the post history. To go to the page dedicated to the post, the user must go to the ellipsis menu and click "permalink".
In Twitter and Facebook, and in many blogs around the web the date links to the post. (Twitter and LiveJournal do it using the title, but that's not great - it may be useful to highlight and copy the title, which is hard to do when it's a link.)
A link to the history should appear in the ellipsis menu.
(The above is based on my intuition. Maybe analytics will show otherwise.)