  Polarized microwave emission from dust is an important foreground that may
contaminate polarized CMB studies unless carefully accounted for. We discuss
potential difficulties associated with this foreground, namely, the existence
of different grain populations with very different emission/polarization
properties and variations of the polarization yield with grain temperature. In
particular, we discuss observational evidence in favor of rotational emission
from tiny PAH particles with dipole moments, i.e. ``spinning dust'', and also
consider magneto-dipole emission from strongly magnetized grains. We argue that
in terms of polarization, the magneto-dipole emission may dominate even if its
contribution to total emissivity is subdominant. Addressing polarized emission
at frequencies larger than approsimately 100 GHz, we discuss the complications
arising from the existence of dust components with different temperatures and
possibly different alignment properties.
