Still not clear about BI then don't worry. You don't need to understand BI in order to use Google fusion tables.
Google Fusion Tables is Google's latest (okay, not that latest ... :P ) experiment on data analysis. It is handy tool to analyze your data and convert that data into meaningful form by generation charts , summaries and maps. These meaningful data makes a lot of sense. Want to learn how to make better sense out of data? Take a look at Google's online course Making sense with Google.
To take more closer look at Fusion table please refer this link.
Doubts , queries are most welcome.