Metal-organic frameworks (MOFs) show world records in BET surface and specific pore volume. An impressive number of different MOF structures has been developed in the last 15 years. In numerous reviews, MOFs are predicted to substitute zeolites and other molecular sieves in big adsorption, permeation and heterogeneous catalysis applications. This short review critically highlights some prominent MOF properties like pore volume and BET surface. It is predicted, that commercialization of MOFs will takes place first in small niche applications, and-if successful-the big processes will follow.