Recent changes to the Jetpack plugin for WordPress have left accounts disconnected.

To remedy this, perform the following steps:
1. Login to your blogs account as an admin.
2. Go to the Installed Plugins item on the Administration menu (under Plugins)
3. Locate the Jetpack plugin
4. Click ‘Activate’
5. You should see Jetpack appear in the Administration menu on the left hand side.
6. Click on Jetpack in the Administration menu.
7. Click ‘Connect to WordPress.com’.
8. Enter your account and password.
9. Jetpack should now be setup and working.