It is true that with the explosion of social networks and instant messaging in recent years, the use of IRC has been progressively decreasing, but it still has thousands of loyal daily users.
In Windows, the client's choice is usually mIRC or one of its reliable alternatives, but for Mac things are more justified And from my point of view there is only one really interesting client that is free: Colloquy.
With an interface that can be quite reminiscent of Adium at times, this application is great for connecting to IRC and chatting a bit, although hardcore users may feel a bit weird with so much graphics ...
Link | colloquy
To connect to this network, users need to make use of a BitTorrent client application, since there are several alternatives for this type of application on the web ... However, Linux users are somewhat more limited in terms of clients for the BitTorrent network although that does not mean that we do not have applications capable of connecting to this network and working properly. This is how there are programs like Deluge, a BitTorrent client for Linux that is distributed as a great alternative and is considered by many to be Linux's uTorrent. Like the most famous and used BitTorrent clients for Windows, Deluge allows you to work efficiently with files .torrent to consolidate the tracking and seeeding data of the files that we need to download.