I'm no expert in SQL Azure, I haven't even had my invitation code yet, also I'm not sure on what the pricing model will be once the CTP is over so this is all speculative, but for us there could be a number of possibilities.

We're never going to be able to get directors to buy in to putting sensitive or critical data out in the cloud straight away, but there are a few database candidates here where it could work out a lot more cost effective to farm them out to the cloud.

One example: We sell insurance, and the majority of our retail business comes via the web. Our main site relies on a tiny SQL database that just contains 'reference data', like drop downs, up to date motor info etc. Nothing sensitive, risk info etc all goes elsewhere via other web services. But if that database wasn't available the site wouldn't work and we'd lose a lot of business. It costs to have the high availability clusters and the DR redundant hardware and data centres that it takes to keep that one database online 24/7 come hell or high water, and I wonder what the cost difference will be in hosting that on Azure?

EDIT: typo