Some details on approaches to including items with no interactions (like brand new products) in your recommender system can be found in this paper "Feature Based Recommendation System" (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.99.4058&rep=rep1&type=pdf).
I'm currently doing some research on this and find the ideas quite appealing but have not yet found a good way to implement this. It's basically stating what was already said here: use the attributes (features) of new items to find similar items for which you can make predicitions. Regards, Sebastian
