Windows Azure Notification Hubs

Windows Azure Notification Hubs was just released for general availability.  These hubs help mobile app developers deliver large numbers of push notifications to mobile users on a wide range of platform.Windows Azure Notification Hubs makes sending push notifications through multiple notification services achievable with just a few lines of code.  Today, apps like the Bing News for Windows 8 are using notification to send millions of push notifications to inform users of the latest breaking news. 

This doesn't replace Windows Azure Mobile Services, which  also supports push notifications. The table below explains the differences.   In short, Mobile Services is best used for communicating to a single user whereas Notification Hubs is best used for communicating to many users simultaneously.

	Mobile Services	Notification Hubs
MPNS, WNS, APNS, and GCM support	Yes	Yes
Turnkey event-triggered push	Yes	No
Device registration management	No	Yes
Interest tags for routing messages to a subset of users	No	Yes
Templates for formatting messages to user preferences including language	No	Yes
Broadcast to >1 million devices at once within minutes	No	Yes

Check out Scott Gu's post for more details.