Cloud computing wouldn't be what it is if it wasn't somewhat . . . er, cloudy. While many of the long-term answers relating to the benefits and pitfalls of cloud computing are still unanswered, the director of IBM Australia's development lab, Glenn Wightwick believes there are at least six worth asking.

Availability: "What are the service levels that I should expect? It's mostly in relation to public clouds but is also relevant to the way that people might deploy a private cloud. What other elements in that chain could impact the delivery of that service?"

Lock-in: "If you think of the example of an e-mail cloud computing provider, if you were to move all of your enterprise's e-mail on to that platform, and then two years down the track decided that you want to move them somewhere else, what is the physical path that you would perform that migration?"

Privacy and confidentiality: "Where is the data physically stored? Is it stored in Australia, or is with a cloud computing provider in the US and subject to issues around the Patriot Act? Is it encrypted, is it replicated?

Performance: "What will performance be like, particularly if the cloud computing provider is on the other side of the world?"

Reputation: "If you think of a cloud computing provider that hosted a number of different companies, such as with e-mail, you can imagine what would happen if someone sent out a million spam messages. TCP-IP addresses of that computing provider might end up being blacklisted. What will the impact be if you were using that cloud computing service at the same time and were innocently caught up in that reputation problem?"

Licensing: "Is that model going to work where the service is just paid for when needed, or will it require a licence?" -- B Howarth