Everything was working fine under Win8Pro Release Preview and FF (17?)...
Did full Win7Pro SP1 x64 install.
Installed FF 18.0.1, no add-ons; all defaults except turned on "do not track" and changed cookie handling as described:
Logging in to my Hotmail/Outlook.com account (MS upgraded me to Outlook.com in the middle of my troubleshooting) I can access my Hotmail People (Contacts) without difficulty.
I change FF Options -> Privacy -> "Keep cookies until" from "they expire" to "ask every time."
When I go to "Hotmail People", I click on "Allow" for every instance I'm asked to set or modify a cookie.
The content of the "People" page (the contacts themselves) never loads. I just get the "please wait" circling-dots.
I return to the Hotmail "Mail" page (which still works fine, except when addressing a message).
I change FF Options -> Privacy -> "Keep cookies until" from "ask every time" to "they expire."
When I go (back) to Hotmail People, the contacts load fine.
Shouldn't the two scenarios be the same? I prefer to manually handle cookie handling, so this feature is important to me.
PS: With the exception of addressing in Mail; Mail, Calendar and SkyDrive all seem to work fine regardless of which cookie setting is used.
Additional information: I had SSL-only enabled in Hotmail, and SSL-only is required by Outlook.com.
I've done four captures using Fiddler v220.127.116.11.
Each capture starts at the Outlook.com Inbox, then the switch to the "People" page.
1) Captured with cookies set "Until They Expire" (green)
2) Captured with cookies set "Ask Me Every Time" and "Allow" (red)
3) Same as (1)
4) Same as (2)
I don't know Fiddler or HTML well enough to troubleshoot on my own.
If someone would like this file for troubleshooting, please let me know.