SETI is an American project looking for radio signals from extraterrestrial life. The letters stand for, “Search for Extra-Terrestrial Intelligence. Unlike UFOlogy SETI is hard science. Finding anything is difficult as scientists don’t know what to look for or where to look. Originally the United States government funded SETI but now private funds are used which SETI claims prevents them finding many promising possibilities.
Likelihood of success
It's extremely unlikely that SETI will stumble upon a planet like Earth where intelligent life has evolved and developed an advanced technology.  Despite this if one or more Type 2 or Type 3 Galactic civilizations exist in our neighborhood there is a good chance we could contact one of many star systems where they have bases.
Some people are worried that SETI might harm us as aliens may be hostile if we contact them. Even passive listening could expose us to harmful alien computer viruses. Could they without understanding our computers? We do run the risk that hostile aliens could give us harmful information. Friendly aliens could advance us so enormously perhaps the risk is worth taking.