I think it's silly to assume that we will be able to exchange information with other-worldy or other-dimensional life any better than we already do with bizarre Earth creatures such as jellyfish or lizards.
There is a chance that the reports of humanoid lifeforms, like the virtually cliché Greys or Reptilians, exist. There is an even better chance that other dynamic forms that we may interpret as "life" will be strange to the point of near incomprehensibility.
I saw this video linked in Posthuman Blues and thought that this could represent some mode of unfamiliar communication or other function which our minds cannot even associate with.
There's another Related Video of abstract eye candy that is pure computer-generated craziness. I wonder, "what if these weird visual forms were actually some kind of completely alien, unimagined intelligence trying to engage me?" I'd like to know how SETI or NASA or any agency on Earth would propose to interact with such beings...