The excitation of plasmons in metallic nanostructures by light can give rise to pronounced local optical field enhancement with respect to the incident electromagnetic field. The details of these optical near fields depend sensitively on the properties of the nanostructures (material, size and shape), on the light wavelength and polarization, and also on the substrate. In this article we discuss several of these aspects influencing the near-field distribution for a given object and the resulting surface ablation by optical near fields. To this end we use both experimental and simulation techniques. Additionally we will present first results of experiments investigating the light emitted during nanoscale ablation. Finally, we will present an example how plasmon-mediated near-field effects act on the conductance of atomic-size contacts.