I was invited by Stefano Mizzaro to give a lecture in his course in “Web Information Retrieval”. I spoke about “Trust in Recommender Systems: an historical overview and recent developments”. It was a lot of fun (at least for me). And I thought I could share the slides with you. They are in OpenOffice .sxi format (it is an open format, so if you program does not read a commonly used open format, you probably better change it). They are released under a Attribution-ShareAlike Creative Commons licence. This means that if you want to use them you just have to give credit to me and re-share your slides under the same licence. If you don’t want to re-share your derivative work under the same Creative Commons licence, you are still free, free of not using them. Enjoy.