There is one, and it is essentially
> people carrying things around on Segways
Electromagnetic radiation must obey the inverse square law. It spreads spherically through space, so required power for a given SNR raises with distance squared.
Moreover, there are severe interference issues. Once you have several systems communicating on the same bands you get more noise in the relevant frequency bands.
Unlike waves which don't self-interact (i.e. obey the superposition principle, are linear), matter is coherent. If you shoot a hard drive at a distance galaxy (with greater than escape velocity), it may take significant time to get there, but you can travel arbitrarily far for essentially the same energy, as a first approximation.
Of course, as a second approximation there is necessity of guidance/control (because of finite motor precision, target uncertainty, etc), but also the possibility of harvesting energy or photon momentum from stars en route.
Aside from the expansion of the universe there's no theoretical limit as to why a sufficiently advanced probe couldn't propagate information arbitrarily far (if it "refuels" periodically, then its total energy usage is proportional to distance, i.e. linear, but launch cost stays bounded).
In the worst case (perhaps for cosmically large distances) it'd need to colonize a planet en route to rebuild a pristine copy of itself.
"Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."
–Andrew Tanenbaum, 1981
"The only way to actually reach the FedEx point is if transfer rates grow much faster than storage rates. In an intuitive sense, this seems unlikely, since storage and transfer are fundamentally linked—all that data is coming from somewhere and going somewhere (...)"