Complex sentence: The number of reviewers grew from 12,000 in 2005, to 100,000 reviewers in 2006 In 2006, Yelp began a marketing campaign featuring window stickers for store windows.
Split into simpler sentences: The number of reviewers grew from 12,000 in 2005, to 100,000 reviewers in 2006. That year, Yelp began a marketing campaign featuring window stickers for store windows.