Mailfilter is a flexible utility for UNIX (-like) operating systems to get rid of unwanted spam mails, before having to go through the trouble of downloading them into the local computer. It offers support for one or many POP accounts.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.