What precisely is this a duplication of? I searched the link and didn't see it.
You can't really be blamed for not knowing that something was on news.ycombinator.com since looking at the list there is slow and painful. To find yesterday's story, I had to scroll down the page and click "More" about 6 or 7 times and on each listing, I had to hit F3 (find) to search for Uber.
This site doesn't even have a proper search function.
So, don't even worry about it because how can anybody expect you to know?