Some frequencies of electromagnetic waves are used for transmission of information, like radiowaves, microwaves, light, but some not..
What about Low Frequencies?:
Perhaps low frequencies aren't used for transmision simply because the waves haven't got enough energy to reach destiny, but is well known that if you go near a high voltage transmission tower, you can turn on a fluorescent lamp http://www.electric-fields.bris.ac.uk/
Perhaps the intensity of the high voltage gives more photons to interact there, than in a home installation, but the fact is waves are traveling anyway at 50/60 Hz without need any modulation.
There is a limit on how low a frequency can be to put photons into travel?