Stick to the analysis...
...and leave out the record review. A music critic you aren't.
On topic, clearly it was a marketing exercise. Who would ever think otherwise? Even new bands playing in the back of pubs only give away their music as a marketing exercise, so that the fans they build up will one day buy their albums, and more importantly pay to see them play Wembley and wear their t-shirts, as there's more profit in that these days.
I see nothing wrong with downloading In Rainbows for nothing, since they were clearly happy for people to do that. I would also have paid for it, if that was the way to get it.
The new business model is not in free music. It can't and it shouldn't be. It's in making that music accessible, maybe it's the NIN model of giving some but not all away. Maybe it's the Coldplay model of giving the singles away and selling the album. Maybe it's the Radiohead way of scrapping labels, then selling an album for £3. But then, who'd pay for the promotion and the stadium-filling video and flashing lights audiences demand?
I suspect the future is, in fact, with record labels selling music online and in record shops and the minority getting it for free. Like they have since the dawn of cassette.