  Wilkinson Microwave Anisotropy Probe (WMAP) has provided us with the yet
highest resolution all-sky maps of the Cosmic Microwave Background. As a result
of thermal Sunyaev-Zel'dovich effect, clusters of galaxies are imprinted as
tiny, poorly resolved dips on top of primary CMB anisotropies in these maps.
Here, I describe different efforts to extract the physics of Intracluster
Medium (ICM) from the sea of primary CMB, through combining WMAP with
low-redshift galaxy or X-ray cluster surveys. This finally culminates at a mean
(universal) ICM pressure profile, which is for the first time directly
constrained from WMAP 3yr maps, and leads to interesting constraints on the ICM
baryonic budget.
