We will most likely have cataloged and observed hundreds of thousands, if not millions, of exoplanets before we physically reach the nearest star. Unless and until we can travel from system to system at an appreciable fraction of the speed of light (> 10%) then the only practical option available to us for exploring the galaxy is to continue building bigger and better telescopes.

Assuming superluminal travel remains science fiction, it will take thousands of years to explore more than a few light years in any direction, but once we start to seriously toodle around the solar system, then we can start to put up some serious hardware that will be capable of direct observation of exoplanets, including looking for telltale signs of life and technology. So even before we set foot outside our own solar system we should have a very good idea of what's out there, a least within a few dozen light years, and maybe more (I have no idea what the limits are of suitably massive--and I mean really massive--space-borne telescopes... if anyone would care to comment).

Of course, what we will be able to do, can be done (and may already have been done) by other more advanced civilizations (if they exist). We are possibly no more than a couple of hundred years away from being able to build a comprehensive catalog of planets ourselves, so imagine what could be done 1,000 or 2,000 years hence.

Even if we don't discover any other technological civilizations, we should at least be able to start narrowing down the values of a couple of the terms in the Drake equation.

And fears over sending radio signals to other worlds seem a bit nonsensical when you consider that advanced aliens dozens or perhaps even hundreds of light years away can probably already see that Earth is home of abundant life. And anyone observing the night side of our little planet, at least the light leaving it within the past 40-50 years, will probably figure out that something unnatural is making that sodium glare! We already betray our presence to those who care to look in our direction.