  Starbursts produce large numbers of Young Star Clusters (YSCs). Multi-color
photometry in combination with a dedicated SED analysis tool allows to derive
ages, metallicities, ${\rm E_{B-V}}$, and masses including $1 \sigma$
uncertainties for individual clusters and, hence, mass functions for YSC
systems. The mass function, known to be Gaussian for old Globular Cluster (GC)
systems, is still controversial for YSC systems. GC formation is expected in
massive gas-rich spiral -- spiral mergers because of their high global star
formation efficiencies and observed in $\geq 1$ Gyr old merger remnants. Yet it
has not been possible to identify young GCs among YSC populations. We suggest a
compactness parameters involving masses and half-light radii of YSCs to
investigate if young GCs are formed in starbursts and if the ratio of young GCs
to more loosely bound star clusters depends on galaxy type, mass, burst
strength, etc.
