Perhaps "useless" from the perspective of advancing the state of the art?
Facebook is advancing the state of the art wrt computer systems. http://www.stanford.edu/class/ee380/Abstracts/100505.html (plug) is one of the things that they've released.
The "state of the art in computer systems", IMNSHO, is things like Jekyll (bidirectional source-to-source transformation, where the generated C code is readable & editable and can be transformed back into Jekyll), Subtext (programming by copying & editing), Epigram (dependent types let the computer write most of the program for you, interactively), and a few other research projects that most people have never heard of.
HipHop advances the state of the art in the same way that a faster JVM does, or a new VM for that matter.
The claim was that Google was advancing the state of the art and Facebook wasn't.
If you exclude the application of known techniques to new problems or in new situations, Google hasn't advanced the state of the art, so the claim is false.
If you allow the application of known techniques to new problems or in new situations, then Google has advanced the state of the art. However, so has Facebook. (Thrift counts too.)
No, Facebook hasn't done as much, but it's younger.