Ambassadors,
If the Wikimedia community you're active in is interested in participating in continued testing of HTTPS-by-default (beyond logged-in users), and there's consensus to do so, you can sign up for the beta program:
https://blog.wikimedia.org/2013/09/10/https-by-default-beta-program/
You can see more about the roadmap to HTTPS-by-default in Ryan's earlier blog post here:
https://blog.wikimedia.org/2013/08/01/future-https-wikimedia-projects/
Signing up for the beta will mean at minimum that, at some point in the future, pages will be advertised to search engines with the HTTPS prefix (via the canonical link element [1]), so while the HTTP prefix will continue to work at that point, users visiting from search referrals will be directed to HTTPS, provided the search engine respects rel="canonical". We call this "soft-enabling". We have not made a final decision as to whether HTTPS will also be hard-enabled at some point in the future.
In any case, these improvements will eventually be applied consistently across our wikis (with possible continued exemptions for regions like mainland China and Iran where HTTPS traffic is blocked); the point of the beta program is to get early technical feedback.
All best, Erik
[1] https://en.wikipedia.org/wiki/Canonical_link_element