Crowd feedback services offer a new method for acquiring feedback during design. A key problem is that the services only return the feedback without any cues about the people who provided it. In this paper, we investigate two cues of a feedback provider - the effort invested in a feedback task and expertise in the domain. First, we tested how positive and negative cues of a provider's effort and expertise affected perceived quality of the feedback. Results showed both cues affected perceived quality, but primarily when the cues were negative. The results also showed that effort cues affected perceived quality as much as expertise. In a second study, we explored the use of behavioral data for modeling effort for feedback tasks. For a binary classification, the models achieved up to 92% accuracy relative to human raters. This result validates the feasibility of implementing effort cues in crowd services. The contributions of this work will enable increased transparency in crowd feedback services, benefiting both designers and feedback providers.