What the OP is talking about is the "X method" of interstellar communication. It was something that Phillip Morrison first thought about shortly after Project Ozma came up with a negative result: it could be that we just don't quite qualify as "intelligent" yet (by interstellar standards) because we haven't become smart enough to discover the "X" technique to talking to everyone else.
Or, it could be (as much as I think it's wrong, I need to mention it) that we're the only ones around. It's just possible that, even though there are lots and lots of "M class" planets around, and life is everywhere, we may be the only ones within a few million light years that have developed tool usage, mathmattics, and the scientific method. i.e. there could be intelligent creatures out there, but they aren't intelligent in the same way as we are... dolphins are intelligent, but are not technological. The same with whales. Crows are tool users, but so far they haven't shown much conception of logic...
Although planets may be as common as grass on a golf course, and life as abundant as insects living in that self same grass, the number of golfers out there may amount to just a handful... and seperated by unimaginable distances.
Number Two: Conform, Number Six! Conform!
Number Six: I will not be stamped, filed, indexed, briefed, debriefed, or numbered! I am a person.