That the conduction electrons inhabiting nanostructured metals and other conductors can sustain resonances involving the coherent, collective dynamics of the electrons – plasmon resonances – has been known and understood for the better part of a century. These resonances can store great quantities of energy, which on dephasing can result in numerous energetic electrons (and holes) which thermalize by electron-phonon interactions over a few picoseconds. Hot electron phenomena such as enhanced photoemission from plasmonic systems have been known for many years.