BICEP2 from an Observer's Point of View

I provide an observer's view on the recent BICEP2 results. I begin with giving background information on the instrument and CMB polarization measurements. Based on a survey of the current debate, I will provide an overview on the conclusions to be drawn from the BICEP2 measurements which are actually mixed: on the hand, there is no doubt that the results are very important and exciting; on the other hand, it is probably premature to conclude that the observed signal is indeed cosmological.