What type of system allows users to deposit and read messages on a server?

A computer bulletin board is a system that allows users to post messages for others to read, similar to an online forum. It functions as a repository where individuals can deposit messages onto a server, enabling asynchronous communication where users can access and respond to those messages at their convenience. This type of system has been an early form of online communication, allowing users to connect and share information without needing real-time interactions.

Mobile communication, while it does involve sending and receiving messages, typically offers more immediate forms of interaction rather than the structured message posting of a bulletin board. Electronic data interchange focuses on the electronic exchange of structured business documents and is not designed for casual messaging. Video conferencing enables face-to-face communication over the internet, which is different from the model of depositing and reading messages on a server. Therefore, a computer bulletin board is the most accurate match for the description provided.