I've been told that it's a corrosive as well. There's an interesting thread on ADVrider on lubing a chain as well with a reference to a Webbikeworld article. Check the bit at the bottom.

I mentioned using WD40 on connectors, and my automotice electrician nearly cried. It'll ruin your connectors over time. He's done a lot of work in the mining industry as well, not just town cars.