To put things in perspective, a 2 TB SDXC memory card can store 100 HD movies, 60 hours of HD recordings, or 17,000 high-quality photos.
The SD Association said that the new format accelerates SD interface read/write speeds to 104 Mbps this year, with a road map to 300 Mbps set for the future. This means it will work perfectly for storing pictures quickly and storing HD video as it is recorded. The SDXC specification uses Microsoft's exFAT file system to support its large capacity.
Two terabytes would allow everyone to carry their entire media library -- music, photos, and video -- on devices such as mobile phones. Having access to everything no matter where you are is an enticing proposition.
The SD Association said that it will have finalized specs ready for the format in the first half of the year.
In order to be used, device manufacturers will have to support the new format. So far, none have announced that they will.
I expect that to change at some point in the near future.