Simple Similarity for User-Based Collaborative Filtering Systems R package CFF version 1.0 A simple, fast algorithm to find the neighbors and similarities of users in user-based filtering systems, to break free from the complex computation of existing similarity formulas and the ability to solve big data. Software Farimah Houshmand Nanehkaran <hoshmandcomputer@gmail.com> Comprehensive R Archive Network (CRAN) Farimah Houshmand Nanehkaran [aut, cre] (ORCID: <https://orcid.org/0000-0003-1687-1719>, University=Islamic Azad University of Kashan,Kashan,Iran), Seyed Mohammad Reza Lajevardi [ctb] (ORCID: <https://orcid.org/0000-0002-4744-2784>, University=Islamic Azad University of Kashan,Kashan,Iran), Mahmoud Mahlouji Bidgholi [ctb] (ORCID: <https://orcid.org/0000-0001-8895-8501>, University=Islamic Azad University of Kashan,Kashan,Iran) GPL (>= 2) 2020-03-04 application/tgz https://CRAN.R-project.org/package=CFF doi:10.32614/CRAN.package.CFF