Difference between Information Retrieval and Information Filtering

Information retrieval is about fulfilling immediate queries from a library of information available.

Example : you have a deal store containing 100 deals and a query comes from a user. You show the deals that are relevant to that query.

Information Filtering is about processing a stream of information to match your static set of likes, tastes and preferrences.

Example : a clipper service which reads all the news articles published today and serves you content that is relevant to you based on your likes and interests.