Radio message to aliens

When a planet or a group of planets (theoretical) chance of intelligent life from Earth can send a radio message, which over many years on the planet or planets will arrive. If the radio message is received and understood, the aliens know that there is life on Earth and they might send something back. This form of communication is problematic:

The likelihood that extraterrestrial beings in intelligence and technology at the same level as us, is very small. The aliens may be less well developed, so that our radio message is not received. After all, life exists on Earth about 3.5 billion years, but use radio waves to send messages only since the end of the 19th century possible. If aliens contrast, more developed, they might use no more radio and they are no longer interested in intelligent life that - in their eyes - even such primitive communication serves. If these more advanced beings are interested in us, then they will with their advanced technologies we probably much sooner than we need them. In addition, the first place but still the question of whether intelligent life on another planet in a similar way as on Earth develops and uses technology (as we know).