Riddle is leading in Top 10K Sites, Top 100K Sites and Top 1M Sites.
Zimbio has better usage coverage in more websites categories. Including Arts & Entertainment, People & Society, Music & Audio, Business & Industry and 36 other categories.
Riddle is leading in Career & Education, Education, Sports, Books & Literature and 33 other categories.
Riddle is leading in most countries, including United Kingdom, France, Germany, Brazil and 26 other countries.
Zimbio is leading in United States, Sweden, Spain, Poland and 23 other countries.