If you make a good ground for your antenna and coax it will attract lightning. If you do not ground, the lightning will select your neighbours grounded tv antenna as its victim.
Sorry, but I do not agree with this, and I think it's colossally bad advice.
In the United States, the National Electric Code requires proper grounding of antennas.
Not grounding equipment and thinking that will protect your system is a rather foolish approach. Lightning
will find it's path, and a fraction of a millimeter of insulation on the cable, in the radio, or on the power wiring will not stop a high energy bolt of lightning. Remember, it travels thousands of feet through the air to get where it's going.
And direct strikes are not the only issue. Even a nearby strike and induce enough energy to damage equipment, start a fire, or injure someone. Relying on a strike hitting your neighbors house, a lamp post, power pole or something else will not guarantee your equipment will survive.
Overvoltage protection between inner lead and coax shield are always a good idea and having the coax curled up with air between the turns makes it an inductive coil that will make the lightning take another route to ground instead of your equipment inside the house.
No. While it may encourage the energy to find another path, the induced energy from even a nearby strike will do damage, coiled coax or not.
The current from a lightning are so high than any type of cable goes high impedance and doesn't protect from a hit. You'll need something like a huge waterpipe that goes deep into ground to have a chance agains a lighting strike. Better then to try and avoid it completly in the first place and have somebody else trying to ground that huge lightning strike energy.
Commercial radio sites handle this by having a network of ground rods. The design of the system depends on the conductivity of the soil.
Again, not grounding and thinking that it will protect your equipment is foolish. If it has worked for you, it is simply because you have been lucky. Designing a system based on luck only works for so long and certainly shouldn't be given out as advice to others. Even if it did work, it would require others to do a proper job of grounding, and I've found that in the majority of hobby and consumer installations, there is no grounding at all.
If you power your house from hanging power lines it will be a source for high voltage spikes and you should concentrate your efforts into making that power box at you house really well grounded and over voltage secured.
This part is correct.