BLL design question

Hello,
 So in the typical 3-tiered approach with DAL, BLL and presentation layer, I have seen basically 2 different ways to use the bll. One is to have the BLL simply return things such as a list of business objects, or a single business object. To bind a grid, you would do something like this: grid.datasource = bll.getcustomers().  A second approach I have seen is to have the BLL contain the list or the single object, so that you would bind your grid like this:  grid.datasource = bll.customerlist.  So which is considered the better approach? Does it matter one way or the other?
tia.
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