System Analytics and Cloud Computing / SaaS

I’ve just read an interesting post on this topic on ZDnet, making the case that the advent of cloud computing is going to raise users’ expectations of performance, which will in turn drive the need for a much higher level of analytical information on the performance of all the key elements of the cloud infrastructure. A main contributor to the post works for a company which (as far as I can tell) provides powerful analytics of log files.I am reminded again of the key role that should be being played by the analysis of existing application usage information, in developing plans for a move to SaaS, and I wonder how organizations address this topic when planning their move to SaaS. How do they assess the real bandwidth needs, without knowing what the real application usage is?If you are engaged in considering, planning or executing a move to SaaS for any current applications, please comment below.  I truly am curious as to how you are assessing the demands on the architecture.