Some of the larger channels had over 350 users chatting at any given time. On channels related to MP3s, the topics tend to be types of music or the type of exchange allowed. The majority of channels observed did not allow trading but, instead, offered leech servers the ability to just search and order up the file you want, no strings attached. More on this later. The application allows you to select which server you want to connect to and, once connected, allows you to search out the particular channel or channels you want to join.
All conversations take place in real time.
That's one of the fortes of IRC, and one of the reasons IRC has been used extensively for live coverage of world events, news, sports commentary, etc. It also serves as an extremely inexpensive substitute for long distance calling. As I soon discovered, people from all corners of the world can be found on IRC and they are serving up MP3 files in a huge way. Once connected, I used the channel search function to locate channels that had MP3 in their names. I 'lurked', or watched, for a while to see how things worked.