PowerPivot CTP3 Hierarchies Make All The Difference

I have been around OLAP databases since 1994. By "around" I mean that I have used them off and on for all those years without actually becoming a true BI dev - rather I am an occasional consumer.

This is because I have focused on Excel and Access and SQL Server (and lately SharePoint), developing transactional databases and budgeting and reporting documents using standard aggregations of business data. Having the data ensconced in a Data Warehouse with OLAP dimensions and Fact tables occasionally has been a big asset for me and frankly I've never understood why BI isn't more broadly used.