What’s the difference between Shared and Dedicated bandwidth?

With unmetered / unlimited shared bandwidth there is no limit set on your account for the amount of traffic visiting your sites. You have a 10Mbs connection but the bandwidth is shared with other users.
Dedicated or CDR bandwidth is available as an option. It is purchased in 1Mbps chunks and guarantees the connection speed, no matter what other users are doing, with no charge for the amount of traffic.