Enough of the sky is scanned on a regular basis to be able to note a very high speed object within a couple of hundred light years of Earth, and the radiation would not just be emitted ahead of the object in just one direction, it probably would still be very bright if it is moving parallel to our orbit around the galaxy. There simply is no evidence of technologically advanced life out there, and based upon that, I conclude we are alone. A civilization at our technological level would be blasting huge amounts of EM radiation (radio, TV, radar) that is probably easily detectable over a couple hundred light years too.
Not really. First, we haven't really been broadcasting for more than about 115 to 120 years, so none of our signals could be any further than that. Second, signal strength is inversely proportional to the square of the distance between the transmitter and the receiver (as a basic rule). By the time our signals get that far out they'd most likely be almost impossible to detect, particularly against the background of the Sun's and the Solar System's own radio/EM emissions.
