Prototyping

Recently, I read an article by Jeff Reagan about data warehouse prototyping (he calls it virtual prototyping). I've seen similar concepts proposed to support data mining and data quality programs. I've also come across some tools that might enhance the experience of the end-user in a prototyped environment. The greatest selling point of this type of prototyping is that you can use it to prove business value without the heavy investment in time and money that often occur when a BI program is implemented. Another great feature was the ability to share in an interactive way the proposed results of a specific BI project which not only would excite them about the business initiatives that the BI/DW program will support but creates a potential for end-user involvement that helps insure the success of your BI program. It may even allow for new or improved requirements. These were some of the advantages presented, can you think of any more? Do you think this could solve certain issues with your BI program? What problems could this create?