Can BW run without a SAP R/3 implementation? I assume it can, but I wanted to be sure. We are planning on evaluating BWs use in loading non-SAP data, while another part of the organization is working on doing the actual R/3 implementation.
Certainly. You can run BW without R/3 implementation. You can use pre-defined business content in BW using your non-SAP data. Here you simply need to map the transfer structures associated with BW data sources (InfoCubes, ODS tables) to the inbound data files or use 3rd part tool to connect your flat files and other data sources and load data in BW. Several third party ETL products such as Acta, Infomatica, DataStage and others will have been certified to load data in BW.
Recently, SAP signed an agreement with DataStage folks to bundled-in the DataStage ETL product in BW 3.0x. This will automate and simplify non-SAP R/3 data source integration with BW.
In my book "Business Information Warehouse for SAP", I have one full chapter on how to load data using flat files and another chapter on how to use 3rd Party ETL products (Informatica for example) to load non-R/3 data in BW. Take a look at these chapters. They will answer your questions.