When you mention BI in the Cloud amongst database vendors and BI practitioners, chances are you'll land on the topic of performance within the first minute or two of the conversation.  Until recently, there was little to debate as limited image sizes, slow storage and shared networks limited the performance of Hardware-as-a-Service (HaaS) based solutions. However, recently Amazon announced the availability of Cluster Compute Instances for Amazon's Elastic Computing Cloud (EC2).  Cluster Compute Instances provide more CPU than any other Amazon EC2 instance. Customers can also group Cluster Compute Instances into clusters allowing applications to get the low-latency network performance required for tightly coupled, node-to-node communication (typical of many BI architectures). Cluster Compute Instances also provide significantly increased network throughput making them well suited for customer applications that need to perform network-intensive operations.

It won't be long before purpose built Clouds start to hit the market, designed specifically to meet the high compute and i/o demands of BI.  Kognitio is already providing a SaaS based solution for hosted data warehouses and front-end BI applications.  From my standpoint, it won't be long before performance will drop off the list of top BI in the Cloud concerns and BI practitioners will wonder why they ever implemented and managed onsite BI architectures.