Expansion ports are sockets or slots in the notebook that allow you to connect peripherals such as modems, disk drives, printers, scanners, and other devices. The more slots, the easier it will be for you to increase the functionality of your computer.
Most notebooks have a common and relatively standard set of such ports.
If you already own some peripheral devices that you want to connect to your new system, make sure the ports on the system and on the peripheral devices are compatible. Otherwise, you will have to purchase expensive adapters or buy entirely new peripherals. Trackpads are small, flat, touch-sensitive areas typically on the hand rest in front of the keyboard, which allow you to move the cursor according to your finger movements. Preferences are extremely subjective, so you will probably have to find physical examples of each to test out. You may also want to consider purchasing a separate mouse, since many users find that a mouse is still superior to pointing devices.