[namdas]

For a popular article that will earn a lot of links its also a good strategy to change the title multiple times during its viral phase. Since many people/cm systems link with the title tag it means you get a wider mix of anchor text which can help the article to rank for a more diverse set of key phrases

[tedmiston]

I've noticed New York Times does this too.

https://mobile.twitter.com/nyt_diff