y4d is a free Chrome add-on developed by Toru Nagashima that enhances the formatting and readability of messages on Yammer. It specifically focuses on code snippets and provides users with a range of formatting options to make their messages more visually appealing and organized.

With y4d, users can easily decorate their messages by applying formatting styles such as bold, italic, underline, and strikethrough. Additionally, they can highlight code snippets using the GitHub-style notation, making it easier for others to read and understand the code.

One unique feature of y4d is its ability to convert spaces to multibyte-spaces before submitting messages. This can be particularly useful for non-y4d users, as it ensures that the formatting of code snippets is preserved even when viewed by individuals who do not have the add-on installed.

Overall, y4d is a valuable tool for developers and anyone who frequently uses code snippets in their Yammer messages. It simplifies the process of formatting and highlighting code, making it easier to communicate and collaborate effectively within the Yammer platform.