What is the current state of research in quantum gravity? I was browsing through this and was wondering what progress in quantum gravity research has taken place since the (preprint) publication.
If anyone can provide some helpful feedback I would be greatly appreciative.
 A: In string theory, string phenomenology has been gaining interest, with the eventual aim of figuring out the experimentally compatible vacuum in the string theory landscape. An example of the success of the field is the MSSM's (which was shown by Kumar, Kane and Acharya to arise in realistic M(atrix) theory vacua, see e.g. [1]) correct prediction of the Higgs mass prior to its actual empirical discovery*. See e.g. TRF.
*As noted in the comments, the KKA paper I linked to came after the discovery -- however, the original paper [2] was from earlier, as pointed out by Matt Reece, and of course the MSSM prediction was known for much earlier than the observation.
A: Approaches to Quantum Gravity: Toward a New Understanding of Space, Time and Matter by Daniele Oriti.
A: A few developments since 2001:
There is the new field of loop quantum cosmology, which shows some promising signs of being able to actually calculate things that might conceivably be testable by observation.
The LHC hasn't found any evidence of supersymmetry, which may reduce the appeal of string theory.
There have been some high-precision tests of dispersion of the vacuum: http://arxiv.org/abs/0908.1832 . The results have been negative. This was at one time though to be a potential test of LQG, but now it looks like LQG doesn't yet make any definite prediction.
LQG has been reformulated in the last 10 years, so if you're going to try to learn it, you want to learn it from more recent references. A presentation of the new LQG is given in Rovelli, 2011, "Zakopane lectures on loop gravity," http://arxiv.org/abs/1102.3660 .
In 2004 there was an internet debate between Smolin and Susskind on Smolin's claim that "the Anthropic Principle ... cannot yield any falsifiable predictions, and therefore cannot be a part of science:" http://www.edge.org/3rd_culture/smolin_susskind04/smolin_susskind.html
