  We apply spherical needlets to the Wilkinson Microwave Anisotropy Probe
5-year cosmic microwave background (CMB) dataset, to search for imprints of
non-isotropic features in the CMB sky. We use the needlets localization
properties to resolve peculiar features in the CMB sky and to study how these
features contribute to the anisotropy power spectrum of the CMB. In addition to
the now well-known "cold spot" of the CMB map in the southern hemisphere, we
also find two hot spots at greater than 99% confidence level, again in the
southern hemisphere and closer to the Galactic plane. While the cold spot
contributes to the anisotropy power spectrum in the multipoles between l=6 to
l=33, the hot spots are found to be dominating the anisotropy power in the
range between l=6 and l=18. Masking both the cold and the two hot spots results
in a reduction by about 15% in the amplitude of the angular power spectrum of
CMB around l=10. The resulting changes to the cosmological parameters when the
power spectrum is estimated masking these features (in addition to the WMAP
team's KQ85 mask) are within the 1$\sigma$ errors published with the WMAP mask
only. We also study the asymmetry between the angular power spectra evaluated
on the northern and southern hemispheres. When the features detected by
needlets are masked, we find that the difference in the power, measured in
terms of the anisotropy variance between l=4 and l=18, is reduced by a factor
2. We make available a mask related to needlet features for more detailed
studies on asymmetries in the CMB anisotropy sky.
