You participate in each topic by reading its postings through to the end, at which point you have the option of making a posting of your own. In a single Motet session you will typically cycle through a number of topics in several conferences. The next time you log in, the system can show you only the new postings in topics that have had activity since your previous visit. Each conference is typically maintained by one or more hosts, who are assigned the job of conference upkeep and given a few special privileges to make that job easier. Hosts can keep topics lively, mediate or terminate disputes, and post useful information.
Hosts are also usually the first people to create topics in a conference.