>but could (like many crawlers) easily be modified by thoughtless or malicious people to impose a heavy burden on sites. Because of this I’ve decided to postpone (possibly indefinitely) releasing the code.

I came here to state just this. What would code for the crawler in the article do that premade DDoS bots don't already do? (already does that task better too) Even in 2012 when the article was published, there were plenty of open source crawlers AND tools designed specifically for "burdening websites with traffic" that were available.