The F-GAMMA program is among the most comprehensive efforts to probe the AGN physics via tracing the evolution of the broad-band radio spectra of some 65 selected Fermi blazars. It covers the range between 2.6 and 345 GHz at 12 frequency steps by utilizing the Effelsberg 100-m, Pico Veleta 30-m and the APEX telescopes in a monthly monitoring fashion since January 2007. The spectra coherency is better than 10 days and the achieved precision of the order of less than a few percent. Here we discuss the sample in its initial and revised form and present studies on the basis of the first five years of data (January 2007 - January 2012).

Specifically, (a) we present the results of a detailed time series and cross-band analysis applied to the five-year data set and investigate correlations with source physical properties as well as test predictions of shock-in-jet models; (b) We propose a phenomenological classification of the spectral variability patterns which, as we show, can be well reproduced with only modest coverage of the source parameter space, assuming that the variability is due to internal shocks; (c) we discuss bias-free Flux(radio) - Flux(gamma) correlations seen at short-mm bands; (d) we study the radio variability amplitude by means of “intrinsic modulation index” and investigate how it influences the Fermi detectability.