The play cost of operations and events is increased by 1.
You can find Donut in the park on Thursday afternoons, playing backgammon. You want his attention, the price is always the same: a cup of coffee and a donut. That buys you a seat at the backgammon table, and you have until he beats you to talk business and set the price.
Imagine that the runner has 3 tags and an installed copy of Donut Taganes. As the corporation with a heap of money, I play Psychographics. What is the maximum I am able to pay, and what will the effect be? You cannot pay more than 3 for Psychographics due to the restriction on the card. So with Donut installed, you can pay 3 (2 +1 for Donut) and then place up to 3 advancement tokens on a card.