No calendar subscriptions showing up on iCloud.com I have a number of calendars on the Calendar app on my MacBook Pro (OS X Mountain Lion 10.8.2): along with the three standard iCloud calendars (Calendar, Home, Work) I have 7 subscriptions. I have tried a number of things, but it seems none of my calendars except the three standard ones want to appear on iCloud.com. Is this an irreparable bug with the Apple software/servers, or is there something I can do to fix this issue here?

Note: It's odd that the calendars and indeed the list of iCloud subscriptions still seems to sync fine with my iPhone. It's just that none of them display on iCloud.com for whatever reason!
This is likely because iCloud.com only has iCloud calendars. Chances are all the rest of your calendars are not iCloud. Honestly, I wouldn't see it as a bug, but something that they haven't added into the online portal. If you click the Settings icon and select Preferences in iCloud.com/#calendar it will not give you an option to add outside calendars.

They will still show up on your phone because it is tied in with your email. If you go to the email account that you are subscribed with, you should see Calendars set to "On".