Category filter is represented by 18 categories which were formed from more than 130 topics that we have at the moment. Discovery keywords search looks for occurrences of the keyword in captions and bios to find the influencers who talk about the keyword. We also rely on a sophisticated matrix of keywords that are used alongside with the keyword and weigh them by joint usage frequency. Using that mechanism we sort influencers by relevance, which ensures that you find the person whose opinion about the subject is relevant to their audience.