The license info in the footer of every Stack Exchange page contains a link to the blog post Attribution Required. In this post, Jeff Atwood explains what the attribution is required to contain.
However, that list misses an important part: CC BY-SA 3.0 also requires a reference to itself, the license.
The legal code says:
You must include a copy of, or the Uniform Resource Identifier (URI) for, this License with every copy of the Work You Distribute or Publicly Perform.
4(b) (for adaptions of the work):
You must include a copy of, or the URI for, the Applicable License with every copy of each Adaptation You Distribute or Publicly Perform […]
As this post is linked in the license notice on every page, and contains this nicely formatted list of required things, it’s likely that many people follow it, not knowing that they must also include the license reference.
So I propose to either update the blog post (*) accordingly, or to replace the link with a link to a new separate page (hosted at stackexchange.com respectively in the Help area of every SE site (**)), as the format of a blog post (publication date, comments) doesn’t seem to be appropriate for such an important resource.
(*) And all other places this is missing, e.g.,