Time is money, people only skim read websites, like newspapers, and supermarkets.
People skim - they don't want all day at the supermarket, and don't want to be bombarded by irrelevant stuff.
Imagine this -
you head to the supermarket, traffics hectic, the crowd is over bearing, all you want is your groceries so you can get home. You enter the car park and the advertisements are spread everywhere tempting you to buy, you reach the door and smell the fresh cooked buns, you reach for a shopping basket but there are none so you settle for a huge trolley. You battle your way through the isles being tempted by advertisements for chocolate, discounts on your favourite ice cream, coupons for biscuits, you dodge the crazy trolley drivers, coerce your way through the traffic jam on isle 4, bypass the spill on isle 5, block your ears to the screaming children at the lollie counter, and finally you reach your destination, 5 bananas a dozen eggs, and a bag of frozen peas was all you wanted and you are exhausted!