It may be significant that the changed title on the other article is actually the title of the article; the older title is not. (Unless someone persuaded the author to change the title on their own site as well as changing here...)
pg often asks people to change the title if they're editorialising. I posted the Nissan Leaf campaign page with the title "We don't need Flash(TM) anymore for anything ever!" and he emailed me and said "don't editorialise in titles" and changed it to "Nissan Leaf".
The counterargument here being that blog post's title was so generic sounding as to potentially not bring enough attention to the importance of the issue. The HN submission's original title didn't misrepresent the contents of the blog post in any way and helped attract more attention to the issue.
That was basically what I said to pg - "I'm not want to tell me HN buddies about the Nissan Leaf, the interesting part is their use of HTML5 video to create an ad campaign that would have traditionally been the domain of Flash(TM)".
pg's response was that if I want to share an editorial opinion about something, other than just posting the title of the page, then I should blog about it and then post a link to my blog.
"The Moment Of Truth For AirBnB As User’s Home Is Utterly Trashed "
Previous submission's title changed from:
"AirBnB: Crimes committed against a host"
to
"Violated: A traveler’s lost faith, a difficult lesson learned"