If the title doesn't make sense, I highly recommend reading Animal Farm. When the farm animals overthrow the farmers, the pigs are the leaders. By the end of the book, the pigs have started walking; a grand revolution of government has ultimately produced leaders just like the old. In the Lost episode Exposé, Dr. Arzt states that the pigs are walking when he's questioning the (de-facto) leaders.
In this case, I just read a commentary piece which at one point gives several examples of huge, monolithic, feature-bloated, overly-complex programs. One of them is Firefox.
But as people may or may not remember, Firefox (er, Phoenix) first became popular as a light, focused alternative to Mozilla (now SeaMonkey). (Actually, at that point in time I was happily using Galleon--never used Epiphany either.)
This isn't really a sighting of "pigs walking" because the commentary piece is referring to the perspective of developers of POSIX-ish systems, not the perspective of a user. And speaking as a user, if Firefox adds features to make my browsing better without hindering me from my most common tasks, I won't complain.