Load a complex shape into your datasource by drawing it.
Copy doc/examples/Simplify.py to your PYTHONPATH.
'touch featureserver.cfg' to reload the config.
Open the Layerswitcher, selected "Simplified Layer" checkbox
Zoom in on your shape, and notice that it is simpler
Simplification Factor:
Simplification factor of '1' should show no visible differences: simplification factor of 2 will be 'twice' as simple, but may show some differences between the simplified shape and the actual shape.