  The cosmic background due to the Sunyaev-Zeldovich (SZ) effect is expected to
be the largest signal at mm and cm wavelengths at a resolution of a few
arcminutes. We investigate some simple statistics of SZ maps and their scaling
with the normalization of the matter power spectrum, sigma_8, as well as the
effects of the unknown physics of the intracluster medium on these statistics.
We show that the SZ background provides a significant background for SZ cluster
searches, with the onset of confusion occurring around 10^{14} h^{-1} solar
masses in a cosmology-dependent way, where confusion is defined as typical
errors in recovered flux larger than 20%. The confusion limit, corresponds to
the mass at which there are roughly ten clusters per square degree, with this
number nearly independent of cosmology and cluster gas physics. Typical errors
grow quickly as lower mass objects are included in the catalog.
  We also point out that there is nothing in particular about the rms of the
filtered map that makes it especially well-suited for capturing aspects of the
SZ effect, and other indicators of the one-point SZ probability distribution
function are at least as well suited for the task. For example, the full width
at half maximum of the one point probability distribution has a field-to-field
scatter that is about 60% that of the rms.
  The simplest statistics of SZ maps are largely unaffected by cluster physics
such aspreheating, although the impact of preheating is clear by eye in the
maps.Studies aimed at learning about the physics of the intracluster medium
will apparently require more specialized statistical indicators.
