  We give an update of the situation concerning the effect of electron-electron
interactions on the physics of a neutral graphene system at low energies. We
revise old renormalization group results and the use of 1/N expansion to
address questions of the possible opening of a low-energy gap, and the
magnitude of the graphene fine structure constant. We emphasize the role of
Fermi velocity as the only free parameter determining the transport and
electronic properties of the graphene system and revise its renormalization by
Coulomb interactions in the light of recent experimental evidence.
