Seriously, WD-40 will NOT hurt your chain. Know what WD stands for? Water Displacement.
My mx bike is beat on. 99% of the bikes on this forum aren't ridden as hard and in as horrible conditions as that bike. Yet, that bike gets more care and attention than most bikes on here, seeing as there are hours of prep between weekends.
One of the products I use the most is WD40. After I wash my bike (with simple green and a POWER WASHER which some on here think will magically blow up your bike) I use WD on the chain to remove the water. I then take that same can of WD and wipe down all my plastics, under the fenders, wheels, plastic/rubber engine parts etc. it leaves those parts looking like new. The gloss on my plastics is like I used plexus, I don't get mud build up like I did before I started to do this.
Considering it doesn't harm my graphics or eat at the adhesive, I fail to see how it will do something like eat your o-rings in your chain.
Of course, I use real chain lube to lube the chain... And for those saying you don't need to lube a chain, I can physically feel the resistance of the rear wheel spinning change as I lube it. That resistance with no lube is the cause of friction. Friction causes heat, heat damages rubber o-rings. The increased friction causes faster wear of chain and sprockets. It also reduces fuel efficiency, has an affect on bike performance etc... So why wouldn't you lube your chain??