Here are some blend samples.

top left - two line segments before and after blend

top middle - blend expanded and put over on top of circle, images underneath shows result of pathfinder divide

top right - same as middle but with square and blend rotated 45 degrees

middle left - shows three different looks by just changing blend anchor points

under squares - colour blend between two colour swatches giving a colour "pallet"

bottom left - shape and colour blend

bottom right - blend between two circles creating bevel

blend sample (http://members.shaw.ca/artisticmedia/blendsample.jpg)