To play Acquire via NetAcquire there must always be a hosting user. Hosting can be done on a temporary, semi-permanent, or permanent basis.
It is important to remember that there is NO CENTRAL SERVER that NetAcquire runs on. Of course, there is nothing to stop someone from setting it up to run permanently, and hence, be an ipso facto server.
Also, once a hosting session has started, the host must communicate to all potential players the needed Communication Window information in order for them to connect. How that information is relayed to players is done outside of NetAcquire. This can be done a multitude of ways, sending instant messages, posting on a web page, calling on the phone, prearranging, etc.
The NetAcquire web page has more information about hosting and communicating.