DSL is not affected by how many neighbors are online. Since your pair of wires go back to the DSLAM.
Moisture in the cables or connections can change line capacitance causing speed changes especially if you are on the outer edges of the allowable 18,000 wire foot mark.
I live over 24,000 wire feet away from the central office.
My connection is never better than 1 to 1.2 mbps.
My neighbor worked at the phone company and conditioned my line removing bridge taps etc.
We have an old straight lay pulp cable that runs for about 5 blocks. It has a lead jacket and cracks all time. They have to pressurize the cable with Nitrogen to keep the water out.
I think that old cable is 50 years old or older. I think it is 2400 pairs.
After heavy rains sometimes we lose sync with verizon's servers.
I got DSL by accident since it was not really "available in my area". But basically I have to take it or leave it as it is. It's still better than dial up and a lot cheaper than satellite.
