Now it's been a week since the demo's hit the Wii - will we see or hear if they've been successfull or not in terms of sales.  I would like them to be as I want demo's to be a permanent fixture and maybe somehow rolled out to retail titles. 

They've sold 2 games to me personally and I think it was a good time to launch them alongside the iplayer rollout as some people may have just connected their wii far that.  What do you think - will it affect sales for Wii Ware titles or not?

Certainly. Nintendo has been very stupid to have snobbed demos so far. A lot of great games like Muramasa and LKS would have sold better if the Wii had retail game demos.

I think it will eventually come to that, it will be kinda late, though.

Of course it will increase sales, the real question is will increase sales enough to warrant the cost? I think it will. But the results have yet to be seen.

What costs are there ? (I'm asking, this is not a statement). I would think that from the programming side, all the developers need to do is enter a section of the game with a fixed save file, and cut out from the code the possiblity to proceed beyond a certain point. Not trivial, but not a huge task either and so not expensive  (?)  What else?

And pave a road for pirates to walk on while they're at it.

Storage and bandwidth costs would be fairly high, especially if demos are going to be kept on the channel indefinitely. Demos that are old and no longer downloaded will be a waste of money to keep. Demo development costs would be fairly low as you say, but it would still be a cost to incur. Apart from that you have upkeep, licensing, legal, maintenance, etc, that come with it, which I would imagine build up fairly quickly.

But as long as the increase in sales is enough to warrant those costs then it will have been worth it.

This article on nintendolife.com seems to say it is doing that already.

link

I know I already bought a game because of the demo service but then again I have been downloading games a bit more in the last few months anyway.

Not if you remove all the code beyond the cutoff point...

People have been doing demos for years without added extra content. Its not hard to keep the pirates at bay - hire ninjas.