ET is definitely out there somewhere, it is arrogant of us as a race to believe that we are alone because that means we would be saying "We are the most intelligent form of life in the universe". When will humans discover it? probably in the last 20 years. When will the world's population find out for sure? soon enough. The only dangers facing us from such a discovery are such things as mass hysteria and the depression that many would suffer on learning just how insignificant the human race is in the grand scheme of the universe.
Should we transmit a beacon? Yes, but we should try to put out a static beacon outside of the orbital plane, with a good clear signal that it is of artificial origin, that way we only have to be concerned that ET is looking in the right place, not worrying about it being the right time.
Why do I run SETI? it's a worthwhile project and worth contributing to.
Suggestions? Perhaps if it was possible to scan the Galactic Plane instead of going up and down all the time, we may stand a better chance of finding something. If you are looking for a needle in a haystack, you stand a better chance the more time you spend looking in the haystack and less around the field.