I occasionally will watch a series of infomercials ... sometimes out of boredom but usually just to see what gadgets the manufacturers have come up with. It's curiosity more than anything else.
However, I have bought a couple of items (The Bean Deluxe and Steam Mop). I still have the Bean and if the exercises are done correctly, you actually can feel your abdominals working (but not to the extent the manufacturers would like you to believe). It often gets relegated to the patio as an extra sun lounge or put into storage. However the Steam Mop was an utter and complete dud.