Complex sentence: Those who use crowdsourcing services, also known as crowdsourcers, are motivated by the benefits of crowdsourcing, which are that they can gather large numbers of solutions or information and that it is relatively inexpensive to obtain this work.
Split into simpler sentences: Those who use crowdsourcing services, also known as crowdsourcers, are motivated by the benefits of crowdsourcing. These benefits are that they can gather large numbers of solutions or information and that it is relatively inexpensive to obtain this work.