YouBlock is a free Chrome extension developed by darby.rathbone. It falls under the category of Browsers and is specifically designed as an add-on and tool for YouTube.

This extension aims to address the issue of spam messages in YouTube streaming video chats. With the recent update in YouTube, the extension may experience some bugs, but it generally works well with new messages. However, it is important to note that it may not block old messages that were in the chat before loading. Additionally, it does not allow you to block people who sent messages before your YouTube loaded.

To use YouBlock, simply install the extension, refresh the streaming page, and then "Report message" the spammers once. After doing so, they will no longer show up in your chat. The extension also offers the option to block someone permanently by blocking them once. To remove someone from the blocked list, you can click on the options in the extensions and remove them by clicking the X next to their name.