A proposal discussed here. The full-on proposal is to eliminate any trace of the transit shadow, with a second less energy-intensive option of just cloaking the oxygen in the atmosphere.
This kind of idea is worth taking seriously, although a problem with this proposal seems to be that you have to know which star system is looking at you, or of course you could just point 30 MW lasers in all directions and run them continuously forever. Astronomy grad students seem to think it's a kind of game to deliberately broadcast messages to Sun-like stars. If they actually believe there could be intelligent life in that direction (which many very smart people do) then they're either stupid, or suicidal, like Native Americans building signal fires so the Europeans could find them more easily. Except with probably a much worse outcome.