While many might see product recommendations, such as those offered by Amazon and Netflix, as just another part of everyday online consumption, behind each suggestion is a set of extremely complex and constantly changing algorithms. In an article found at IEEE Spectrum, Joseph A. Konstan and John Riedl, co-founders of Net Perceptions and industry veterans, delve into the history of recommender systems and explain how they work to put the right products in the face of users. Head to the source to see how Facebook recommends friends and why Justin Bieber keeps popping up on your online playlists.