crowdsourcing is described , for example , where solutions to tasks such as designing a logo , writing a piece of code or answering a question are solicited by making open calls to large scale communities . in an example , a crowdsourcing node models a plurality of contests as all - pay auctions , each contest having a task and a reward . in examples , the crowdsourcing node is arranged to set rewards for the contests so that the optimal results are received for each contest owner , those owners having provided a budget and using a utility function for each of the contests . in examples , the crowdsourcing node is arranged to recommend contests to potential participants so that those participants can more easily decide which tasks to take on next .