Yahoo! Messenger Alternatives for Mac OS X

Skype is a versatile communication platform offering free voice and video calls to other Skype users, as well as affordable calls to landlines and mobile phones worldwide. It provides instant messaging, file sharing, and screen sharing features, making it a comprehensive tool for personal and professional connectivity across various devices.

Pidgin is a free and open-source multi-protocol instant messaging client designed to connect users across various chat networks with a single application. It's highly extensible through plugins and supports a wide range of protocols including XMPP, ICQ, and IRC.

Telegram is a fast and secure cloud-based instant messaging platform offering robust privacy features, large group support, file sharing, and cross-platform synchronization, making it a versatile communication tool.

WhatsApp Messenger is a widely used free messaging and calling app, available globally. It enables communication through text, voice messages, and video calls, facilitating connections between individuals and groups across various devices and platforms.

Adium is a free and open-source instant messaging client for macOS, designed to connect to multiple chat networks simultaneously. Supporting protocols like Jabber (XMPP), Google Talk, AOL Instant Messenger (AIM), ICQ, MSN Messenger, and Yahoo! Messenger, Adium provides a unified interface for all your conversations.

Tox is a free, open-source, and secure peer-to-peer instant messaging and video calling protocol designed for strong privacy and censorship resistance. It provides end-to-end encrypted communications without reliance on central servers.

Trillian is a versatile, multi-protocol instant messaging client that unifies various communication platforms like IRC, XMPP, and more into a single, user-friendly interface. It's designed for both personal and team collaboration, offering features like encrypted chats, group collaboration tools, and extensive customization options.

Signal is a secure, open-source messaging application that uses end-to-end encryption to protect user communications. It offers text messaging, voice and video calls, group chats, and file sharing, all with a strong focus on privacy and security. Available on multiple platforms, Signal is a leading choice for individuals prioritizing confidential conversations.

Jitsi is a free and open-source suite of secure, flexible communication tools. It offers multi-platform support for voice (VoIP), video conferencing, and instant messaging, emphasizing privacy and ease of use with no account required to start a meeting.

LINE is a versatile communication platform offering free voice and video calls, messaging, and a wide array of interactive features to connect with friends and family globally. It goes beyond basic chat with unique stickers, timeline posts, and integration with various services, providing a comprehensive social and communication experience in one app.

Psi is a robust, open-source instant messaging client built on the XMPP protocol. It's known for its focus on speed, efficiency, and adherence to XMPP standards, offering a clean interface and strong privacy features for secure and reliable communication.

Wire is a secure, cross-platform messaging and collaboration client offering end-to-end encryption by default for all communication types including messaging, voice and video calls, and file sharing across desktop and mobile devices.

Franz is a free, open-source application that consolidates multiple messaging and chat services into a single, convenient interface. It allows users to manage conversations across platforms like WhatsApp, Telegram, Slack, and more without switching between different apps.

Ring (SFLphone) is a free and open-source communication platform offering secure messaging, voice, and video calls. It leverages decentralization and end-to-end encryption for enhanced privacy across multiple operating systems including Linux, Windows, macOS, and Android.

ICQ is a veteran instant messaging platform offering a wide range of communication features, including text chat, voice and video calls, screen sharing, and group chats. It aims to provide a reliable and feature-rich messaging experience with a focus on privacy and security.

WeChat is a comprehensive mobile app offering instant messaging, social networking, payment services, and access to a wide range of mini-programs. It facilitates communication through text, voice, and video, supports group interactions, and integrates various lifestyle services.

iMessage is a secure instant messaging service developed by Apple, seamlessly integrated across its ecosystem of devices. It allows users to send text messages, photos, videos, audio messages, and more, with end-to-end encryption for enhanced privacy.

qutIM is a free and open-source, multi-protocol instant messenger designed for connecting to various networks including ICQ, Jabber, Mail.Ru, IRC, and VKontakte. It offers a unified interface for managing multiple accounts and conversations.

KakaoTalk is a popular mobile messaging service offering free text, voice, and video calls. Primarily used in South Korea, it provides a comprehensive communication platform with features like group chats, stickers, and a strong emphasis on user privacy and security.

Psi+ is a robust, cross-platform XMPP/Jabber client tailored for users who prioritize control, privacy, and extensibility. As a development branch of the classic Psi client, it offers advanced features for secure and customizable instant messaging.

Rambox is a FOSS and portable messaging and emailing application that consolidates numerous web services into a single, convenient interface. It supports a wide array of communication and collaboration platforms, including popular chat, email, and social media services, offering a unified experience with features like unified inbox and notifications.

Coccinella is a free and open-source, cross-platform XMPP/Jabber client. It offers secure instant messaging, group chat, voice chat, and a unique interactive whiteboard feature. Designed with privacy and security in mind, Coccinella provides encrypted communications and supports various communication protocols for a flexible messaging experience on Windows, macOS, and Linux.

Zulip is a powerful open-source group chat application designed for team collaboration. It uniquely structures conversations around topics, enabling users to easily catch up on important discussions and manage information overload. Zulip facilitates secure communication with integrated file sharing and various integrations.

Tkabber is a free and open-source instant messaging client specifically designed for the XMPP protocol. Built with the Tk toolkit, it offers a lightweight yet extensible platform for text-based chat, group conversations, and various interactive functionalities supported by XMPP.

YakYak is an unofficial desktop client for Google Hangouts, providing a dedicated application experience outside of a web browser with features focused on convenience and improved usability.