What's difference between item-based and content-based collaborative filtering?

Question

I am puzzled about what the item-based recommendation is, as described in the book \"Mahout in Action\". There is the algorithm in the book:

for every item i tha         


        

Answer 1

"Item-based" really means "item-similarity-based". You can put whatever similarity metric you like in here. Yes, if it's based on content, like a cosine similarity over term vectors, you could also call this "content-based".