Claying is a great little process that I think brings great results.
Claying is often reccomended twice a year to remove the harder contaminents that get stuck in the paintwork.
After claying, the car should be washed to remove the solutions the clay can leave behind. Then its just a case of a good polish and seal it all in with a coat of a good wax or two.
Should maintain the paintwork for alot longer than unprotected paint.
Chris
PS: - I havent heard of it damaging the clearcoat but as said above, twice a year should suffice.

Golf 1.4S with Black 'B' Pillar Mod|Black Grille and Badge|8000K HIDs|JVC KD-AVX33 Headunit mounted in Glovebox|In Car PC (Intel Atom 1,6GHZ Mini ITX board|1GB DDR2 RAM @667mhz|160W Car Power Supply|Built in 7" touchscreen)|Vibe Slick A2 Amplifier|Vibe SLR12" Sub|Xenon White Number Plate lights|Blue Interior Bulbs.