  One of the main goals of contemporary theoretical physics is to find the
quantum theory of gravity. There are various working hypotheses, mostly
operating in the regime of high-energy physics well above the reach of particle
accelerators. So far, strong experimental or observational evidence to guide
the theory is missing. A possible consequence of quantum gravity and quantum
spacetime that is often discussed is the vacuum dispersion effect. In this
paper, we consider a different line of quantum space phenomenology, the
behaviour of microscopic black holes. Even though their exact nature is
unknown, some of their features are very model-independent, allowing us to draw
conclusions about their role in the current cosmological models.
