That one is a scanned PDF; its contents don&#x27;t appear to be indexed by, e.g., Google; its availability is dependent on the continued goodwill of the ACM.<p>Paul Graham&#x27;s copy is plain HTML, sitting on the open web where anyone can see it and index it, and while for the rest of us its availability is dependent on PG&#x27;s continued goodwill presumably <i>he</i> likes being able to rely on it staying there as long as he wants unless he&#x27;s explicitly forced to take it down somehow.