Wasn't it Skybuck Flying who wrote:

So has anybody really analyzed the light from stars... if they contain
messages from aliens ?

There are several OSETI (Optical Search for Extraterrestrial
Intelligence) projects in progress at the moment. They tend to be
designed around the idea of the little green men using modulated laser
beams pointed in our direction, because the technology required to build
such a laser is more reasonable than that required to modulate a star.
However, if there are aliens modulating the output of starts, the OSETI
systems will detect that too.

-- 
Mike Williams
Gentleman of Leisure