Much of what we do in the BPM/Workflow space has to due with bridging the gap between business silos within organizations. All businesses of a certain size have them, and in the majority of cases they contribute to inefficiency. However since all businesses have them, are business silos not always a bad thing. Therefore what should you look for to determine when bridging a silo is just, a bridge to far.
Silos come into being for a number of reasons like: companies or generally hierarchical in nature, they may have had mergers and acquisitions, poor planning or just different requirements. Sometimes silos are formed instantly but generally they form over a period of time.