Kile, here's a quick layout of hubs.

Switched Hub - Can be setup to direct network packets to only specified computers or other hubs. Usually this is used in large networks to help reduce network traffic clutter to smaller segments.

Unmanaged hub - Plug and play basicly, there is no management of the hub other than the cables plugged into it.

Managed hub - Certain aspects of the hub functionality can be controled from a remote computer, like bandwidth settings on ports. A Switched hub would be a managed type of hub. What settings you can manage depend on the hub you purchase.

Rob.