Free, easy music distribution over the internet caused underground music scenes to explode as the 2000s began - these styles were characterized in part by musical retromania, and the reappropriation of styles from the 60s, 70s and 80s. The huge variety of music produced in the decade can make it hard to summarise as a whole. Mainstream pop music enjoyed continued success, taking on more influences from hip-hop, R&B and electronica. Electronica and dance music grew more sophisticated as the decade went on. Read more on Last.fm.