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The resistor increases the input impedance by 1K. This limits the input current. (The amount by which it's limited/decreased also depends somewhat on the output impedance of the source.)
Does this matter? If your circuit has a high input impedance already, like input to the gate of a FET or an op-amp, then it doesn't matter very much. Sometimes you may see serial resistors before the gate of a FET or op-amp input anyway, in part for current limiting for protection against static charge, I think. But the amount of current that can go into the gate of a FET is essentially zero. This is why they make good buffers.
On the other forum you mentioned that the circuit was a Fuzz Face. This is one place where it could matter because the input to the transistor is low impedance. So if you have some small noise voltage the transistor can sink current and amplify it (because that's what transistors do) amplifying the noise. Adding the input resistor probably lowers the gain as well as lowering the noise, but maybe you have enough on tap in the circuit that it won't matter.
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