On January 28, 2013, the DCI announced the new Banned and Restricted updates for Gatecrash. Effective February 1, 2013, in live events and February 6, 2013, for Magic Online, the following changes will take effect:

Modern

Bloodbraid Elf and Seething Song are banned.

Magic Online Pauper

Empty the Warrens, Grapeshot, and Invigorate are banned.

Standard, Extended, Legacy, and Vintage

No changes.

Changes to Magic Online-only formats are now announced monthly in the Magic Online Community Group blog.

For the complete list of all banned and restricted cards by format, click here.

An explanation of the changes by Erik Lauer on DailyMTG can be found here.