Hackollapse is a Chrome add-on developed by mattcolemanr that provides a better way to interact with comments on Hacker News. With this add-on, users can easily collapse entire comment threads from anywhere in the tree, allowing for a more streamlined reading experience.

One of the main features of Hackollapse is the ability to quickly see how many children a comment has, which helps users gauge the depth and complexity of a thread. Additionally, users can hide or show child comments while keeping the parent comment expanded, making it easier to focus on specific parts of the discussion.

Hackollapse also offers customizable settings, allowing users to change how the collapse action works. They can choose to have Hacker News remember that they collapsed a comment when clicking the [-] icon, or they can opt for the collapse action to never be remembered. Users can also toggle the visibility of the "hide child comments" action.

Overall, Hackollapse is a useful tool for Hacker News users who want to streamline their reading experience and have more control over comment threads. It is available for free on the Chrome Web Store.