If you rely on Canadian size structural shapes for your work then you'll wish you had a valid subscription if you don't. The Canadian Structural Content Extension for Autodesk® Revit® RST 2015 software provides the latest CISC standard 9.2 hot rolled structural steel shapes is available in the Subscription Center for you to download. This extends the current out-of-the-box content offering, reducing the need for users to seek alternative sources of content.
This was announced via the BIM & BEAM blog earlier today.
I have to admit my first reaction was that it ought to be available regardless of subscription status. I'd prefer that anybody using Revit Structure and relying on accurate structural shapes also has the latest shapes to use. If it is truly supplemental, as opposed to updating critical existing shapes, then perhaps it is a subscription benefit?