I disagree with the "https://news.ycombinator.com/item?id=5489039 versus https://news.ycombinator.com/5489039/if-the-earth-were-100-p... - its in contradiction to the author's earlier point that URLs should be "hackable". With the former style, I know that if I want to see other hackernews articles, I can just change the number (granted, it's not the most efficient way of browsing HN) - with the latter, I can't modify the URL w/out knowing the title of the article I'm looking for.