Miranda IM is an open-source, multi-protocol instant messaging software for Microsoft Windows. Light on system resources, extremely fast, and with a robust plugin-based architecture with over 350 plugins, Miranda is one of the most flexible and customizable messaging clients on the planet.

In terms of protocol support, Miranda IM supports a vast and growing number of protocols, some developed internally but most contributed by community developers. Some of the protocols supported by Miranda are AIM (AOL Instant Messenger), Facebook, Gadu-Gadu, IAX (Inter-Asterisk Exchange), ICQ, IRC (Internet Relay Chat), Jabber, MSN, Netsend, Tlen, and Yahoo. In addition, Miranda also supports several contributed protocols, such as Battle.Net, Bonjour, C6, Google Talk, Facebook, Fetion, iChat, Lotus Sametime, Mail.ru Agent, MeBeam, MySpace, Omegle, QQ, SIP RTC, Skype, Tencent QQ, Twitter, VKontakte and many more.

Miranda is straightforward to use. When you run it for the first time, it will ask you to complete a profile. Add your name or a description, such as "Workplace," and click "Create." Next, Miranda will ask for details of your instant messaging accounts. If you have not yet registered with a network, you can follow the link to register after creating an account for that network in Miranda. If you do not want to use a protocol, it is best to delete the .dll file. To remove dll files, go to the remove plugins section. If you need to change the details of a protocol later, go to Main Menu -> Options -> Network and click on the protocol you want to change.

Once you have set up your accounts, connect your status by clicking on the status menu at the top of the Miranda window and choosing "Connected" or the desired status. Add contacts by clicking "Add Contact" in the main menu or right-clicking in the contacts window. Once you have your contacts added, you can send them messages by simply double-clicking on their name in the contact list and typing your message in the conversation window that opens.

As for software customization, Miranda IM offers a wide variety of options. It is possible to change the appearance of the contact list using different plugins, such as classic, modern, or multi-window support. It is also possible to change the look of the message window using various SRMM plugins, such as Scriver, TabSRMM, or nConvers. In addition, it is possible to add emoticons and avatars for both the user and the contacts, as long as the protocol allows it.

In summary, Miranda IM is a complete and customizable instant messaging software with a wide variety of options to adapt to the needs of each user. Its low resource consumption and high speed make it an excellent choice for those looking for a fast and efficient messaging client.