  The satellite experiment WMAP has produced for the first time a
high-coverage, high resolution survey of the microwave sky, releasing publicly
available data that are likely to remain unrivalled for years to come. Here we
compare the WMAP temperature power spectrum, along with an exhautive
compilation of previous experiments, to models of dark energy that allow for a
tracking epoch at the present, deriving updated bounds on the dark energy
equation of state and the other cosmological parameters. Moreover, we
complement the analysis by including a coupling of the dark energy to dark
matter. The main results are: a) the WMAP data alone constrains the equation of
state of tracking dark energy to be w_\phi<-0.67(-0.49) to 68%(95%) (confining
the analysis to w_\phi>-1), which implies for an inverse power law potential an
exponent \alpha<0.99(2.08); b) the dimensionless coupling to dark matter is
|\beta|<0.07(0.13). Including the results from the supernovae Ia further
constrains the dark energy equation of state.
