[kyorochan]

If ads are not effective, why do you think companies keep buying them? Surely they would have realized by now.

[rchaud]

Companies have ad budgets that must be spent to the last dollar lest that dollar be deducted from next year's budget.

[ej88]

The only reason why have an ad budget is because buying ads was effective. If they were no longer effective there would be no ad budget