Writing articles involves searching, exploring, evaluating and reflecting upon different perspectives. To this end, online search engines are commonly used tools to support writing. However, online search engines, such as Google, fall short in supporting complex queries that satisfy multiple criteria simultaneously. In this paper, we present our studies with GAS, a crowd-powered tool that allows writers to discover viewpoints, solutions and ideas that best fulfil multiple criteria simultaneously. Our user studies validate GAS as a beneficial companion to online search engines in supporting writing. We found that GAS helps people come up with ideas and write with more confidence, resulting in a higher self-reported article quality and accuracy when compared to only using an online search engine. Through our experiments, we also develop an understanding of the distinct process that people employ when searching for and exploring open-ended, subjective information to support exploratory writing.