Cloud Computing presents unique opportunities to companies to reduce costs, outsource non-core functions and scale costs to match demand.

However, the Cloud also presents a new level of complexity that makes ensuring application performance in the Cloud a unique challenge, in particular  with the many different usage and deployment scenarios available.

Perhaps the most popular present scenario uses the Cloud to perform certain tasks where  additional computational power is unavailable in a local environment, e.g.: running large scale load-tests or processing large amounts of input data into something else.

Another scenario which is becoming more attractive these days is to actually run applications in the Cloud.
Read more about the challenges of Monitoring, Tracing and Profiling applications that run in the cloud @

http://blog.dynatrace.com/2009/05/07/challenges-of-monitoring-tracing-and-profiling-your-applications-runing-in-the-cloud/