HN user profiles have a setting called &quot;topcolor&quot; which allows you to change the color of the orange (by default) bar at the top of the page to any color you like. If I remember correctly, the feature is enabled if you have some number of karma points.<p>I find the feature useful to visually differentiate a logged-in HN session (my color) vs. a logged-out HN session (orange).<p>Apparently, this is a list of all the colors that HN users have set their &#x27;topcolors&#x27; to. (I set mine to &#x27;66dd66&#x27;, which indeed shows up on the list.) Why someone found it useful to keep track of this list of colors is anyone&#x27;s guess.<p>It looks like HN is a very diverse community, at least in terms of their favorite colors.