According to IGN and Videogamer, Microsoft is notifying users via Xbox Live Messages that they've received a 7-day subscription. It's not clear if this bonus offer will go out to all Xbox Live Gold members or only those affected by the recent downtime.
We've reached out to Microsoft for more details about the promotion. We'll update this story with more information when it becomes available.
Microsoft's Xbox Live Service Status page reports any issues with the service and provides a timetable for when they might be fixed. Right now, no issues are besetting Xbox Live.