Pinterest is rolling out an expanded search engine on its mobile apps for iOS and Android designed to help you browse your interests more effectively than you can on a traditional search engine. Guided search, as Pinterest is calling the feature, returns a list of Pinterest tiles for your searches that are popular among users. Guided search represents the most significant of three announcements Pinterest made tonight at its headquarters. Guided search and related pins offer advertisers the opportunity to target potential customers with a high level of precision.