Hacker News keyboard navigation is a free Chrome add-on developed by Zeeingsoft. This add-on allows users to navigate Hacker News using only their keyboard.

One of the unique features of Hacker News is the "hide" button, which allows users to hide posts they are not interested in. However, clicking the "hide" button for each post can be time-consuming.

With Hacker News keyboard navigation, users can easily navigate through the list of posts using the arrow keys. Pressing the up and down arrow keys allows users to move up and down the list. The left arrow key can be used to mark a post as not interested or hide it.

Additionally, the right arrow key opens the link of a post in a new background tab, while the enter key opens the link in a new foreground tab. Pressing the space bar opens the comments section of a post.

Overall, Hacker News keyboard navigation provides a convenient way for users to navigate Hacker News using only their keyboard, saving them time and improving their browsing experience.