Skillet (band) 2000, Trey McClurkin parted ways with Skillet, and Lori Peters filled the drummer's position. The band released their first worship album, and fourth album overall, "Ardent Worship" in late 2000. The band kept much of their sound from "Invincible" on their next album "Alien Youth". With little time between touring and recording, Skillet released "Alien Youth" on August 28, 2001, which was the first album that John Cooper took on production duties. Before the release of "Alien Youth", Haaland left the band, and Ben Kasica took over on guitar. In 2003, "Collide", the band's sixth studio album, was released by
Item-item collaborative filtering Item-item collaborative filtering Item-item collaborative filtering, or item-based, or item-to-item, is a form of collaborative filtering for recommender systems based on the similarity between items calculated using people's ratings of those items. Item-item collaborative filtering was invented and used by Amazon.com in 1998. It was first published in an academic conference in 2001. The authors of that paper, Badrul Sarwar, George Karypis, Joseph Konstan, and John Riedl, won the 2016 "Test of Time Award" for their paper "Item-based collaborative filtering recommendation algorithms". The International World Wide Web Conference committee stated that "this outstanding paper has had a considerable real-world impact".