A change in content broadcast from Earth
Since the 1930s, we've been broadcasting signals into space over electromagnetic waves. These waves have carried radio and TV, but not the Internet. The Internet is not broadcast in the same way. It does not reach space. Thus, all the cat pictures and troll memes and fortunately Trump's twitter feed do not get broadcast out to other worlds.
Science education likes to tout the fact that our signals make it to other worlds and that alien civilizations may be able to receive our signals. But eventually we may not broadcast anything interesting, and yet we would still be generating interesting content, but it would be contained within the Internet. Likewise, alien civilizations may also have evolved past the point that they broadcast significant signals into space simply because it's not necessary. The estimates provided for the Drake equation like to limit the lifetime of a civilization based on how likely it is to destroy itself. But what if the civilization simply goes dark so to say by containing it's signals within wires and fiber. From an outside point of view they would simply go dark and seem to have ceased to exist.
We probably also should consider rising use of encryption. Sure, the signal that gets broadcast would still be binary, trinary or the base level of it would be irregular from natural phenomenon, but we still are very unlikely to be able to decrypt it. In just 200 years we've gone from not being able to communicate at near light speeds to not only doing so, but doing so in private. 200 years. That's less than a finger snap in the cosmic scale. So it's more probable that the signals we're receiving are encrypted to levels beyond our abilities. How can we possibly hope to decipher the signals of alien worlds. We need to imagine other ways of discovering alien life than just listening for a signal.