I like the idea that E2 is a constant work in progress and will never really be complete. Thats not to say having it on a DVD or 2 isnt a great idea. It's just that might see E2 become commercial at that point. With E2 commercialized who would contribute to it properly? It would simply become a massively used and abused Encyclopaedia, something like the Hitchhiker's Guide to the Galaxy (may Douglas Adams rest in peace).

You know what happened to the Hitchhiker's guide to the galaxy? It was too successful. Everyone will have a copy and be able to contribute to E2, and that will ruin it. If it's simply a backup that you can purchase for the mere cost of the DVD (a very minute profit margin) then the idea might work. I'd like to see it on a PDA though. Theres nothing thats just as cool as saying "I contain EVERYTHING in my pocket!"