If it is a PR stunt, it's pretty crass. But I doubt it's PR - they don't make any money on links, so a hike in traffic just means more costs. Considering that

If it is a PR stunt, it's pretty crass. But I doubt it's PR - they don't make any money on links, so a hike in traffic just means more costs. Considering that they did intend to keep the old URLs functioning, and that users can get the same free service from dozens of URL shorteners, the whole thing just seems weird.