updated 05:56 pm EDT, Thu September 12, 2013
Move comes after years of lobbying with Microsoft for the functionality
Despite still claiming that Exchange ActiveSync (EAS) is the best option for email, Microsoft today announced that it has added IMAP support to Outlook.com for all users. With the addition also comes the OAuth standard for protected data access and use. The move gives OS X Mail and OS X Thunderbird email clients access to Outlook.com emails for the first time.
In a blog post discussing the upgrade, Microsoft claims that while it believes that "EAS is the most robust protocol for connecting to your email, with syncing in near-real time, and superior battery and network efficiency, there are still some devices and apps that haven't made the upgrade to EAS. As an older protocol, IMAP is widely supported on feature phones and other email clients such as those on a Mac."
Microsoft also revealed that apps TripIt, Sift, Slice, motley*bunch, Unroll.me, OtherInbox, and Context.IO have updated, with implementation of the new IMAP connectivity in Outlook. The company says that it will have "many more to share in the near future."