  The cosmic infrared background (CIB) is a sensitive measure of the star
formation history. But this background is overwhelmed by foregrounds, which
bias the CIB mean flux and auto correlation measurement severely. Since
dominant foregrounds do not correlate with the large scale structure, the cross
correlation of CIB with galaxies is free of such foregrounds and presents as an
unbiased measure of the star formation history. This also allows the
measurement of CIB based on integrated intensity, whose theoretical prediction
is based on energy conservation, thus is fairly model independent and robust.
The redshift information of CIB sources can be directly recovered with the aid
of galaxy photometric redshifts. In the far IR region, correlation signal is
around 10% at degree scale. Combining FIRAS and SDSS, the cross correlation can
be measured with 20% accuracy (statistical and systematics errors) at $l\sim
40$. Such measurement would allow the measurement of star formation rate with
comparable accuracies to $z\sim 1$. Future CIB experiments with $1^{\circ}$
resolution are able to measure the star formation rate with 10% accuracy to
$z\sim 1.5$. Secondary CMB anisotropies arising from the large scale structure
correlate with CIB. The correlation strength is about $0.5\mu$K at $\sim
10^{\circ}$ (the integrated Sachs-Wolfe effect) and $\sim -0.3\mu$K at $\sim
1^{\circ}$ (the Sunyaev Zeldovich effect, Rayleigh-Jeans regime). FIRAS+WMAP
would allow the measurement of the ISW effect with $\ga 5\sigma$ confidence.
Its detection helps to constrain the amount of dark energy and far IR
emissivity bias.
