Just FYI - Sharing a calendar with Outlook 2007 using Exchange 2013 (Office365) no longer works.
support.microsoft.com/.../2836889
~~One of the few great "upgrades" we've gotten with Office365 since we switched (along with the removal of the built-in OWA spellcheck..)
Following the workaround suggested in the KB article I linked, I could set it up in OWA this way, but that still leaves me having to add every user individually to the share list. I'd like have all users added (as well as all new users, by default). It looks like maybe the Security Group approach could achieve some of that, but then I'd have one more list I had to maintain. And I don't want to calendar tied to a user account.
I suspect what I'm hoping to achieve is going to require some Powershell work.