Well, it might preserve information. We don't actually know that it does. As far as I can find out (and I've looked), there is no evidence that the strength of neural network connections - and that's what your mind appears to be stored in - is actually preserved by current cryonics practice. (If you have something that directly addresses that specific question, I'd love to see it.)
And, of course, revival requires not only as-yet uninvented technology, but as-yet unrealised scientific breakthroughs, and the assumption that the scientific breakthroughs we would need will in fact work out the way we would need them to.
This is a profoundly slim chance to pin one’s hopes on, but it does not provably violate physics as we currently know it.
I'd love cryonics to work. I was actually neutral to positive on it before ciphergoth provoked me into investigating for the RW article. But there is no evidence as yet that current practice does or can, only that it might. I feel that being uncompromisingly realistic and rational about the prospects of it working is quite important to behaving sensibly concerning it.
Alcor says:
"It is a well-established fact that long-term memories are encoded in durable physical and chemical changes."
Usually the problem is not with freezing - but with thawing. Vitrification improves things further - but even without that an enormous quantity of information seems bound to be preserved. I don't think scepticism about this has much scientific basis. We know enough about the brain, and about freezing to see that a mountain of information will be preserved.
Also, check out the frozen frogs.
I recently found something that may be of concern to some of the readers here.
On her blog, Melody Maxim, former employee of Suspended Animation, provider of "standby services" for Cryonics Institute customers, describes several examples of gross incompetence in providing those services. Specifically, spending large amounts of money on designing and manufacturing novel perfusion equipment when cheaper, more effective devices that could be adapted to serve their purposes already existed, hiring laymen to perform difficult medical procedures who then botched them, and even finding themselves unable to get their equipment loaded onto a plane because it exceeded the weight limit.
An excerpt from one of her posts, "Why I Believe Cryonics Should Be Regulated":