I’m so glad you asked.  Although varying definitions abound, distilling the essence leaves me with: Business Intelligence is the collection of all of the people, processes, tools and technologies required to deliver data to those who need it in order to act upon it.  The actions taken may range from doing nothing to making critical decisions.

The realm of business intelligence can include reporting, but so much more as well.  Business analysis, data warehousing, data profiling, dimensional modeling, data stewardship, data visualization, development, QA, operations and support (gotta meet your SLAs!), et al.  While there are BI tools, business intelligence is not a tool nor is it an application or a particular technology such as OBIEE or SSAS.

When understood properly, one can see that neither reporting nor extract, transform and load (ETL) activities constitute business intelligence in and of themselves.  Only when the company is truly committed to business intelligence, activities are pulled together into a cohesive and synergistic whole and harnessed for the purpose of delivering data to those who will utilize it for decision-making purposes can the group be considered a true BI team.