The transfers are done in real time and usually require that the user have an account on both machines. However, many machines on the Internet support what is known as anonymous FTP, which allows users on other machines access to a limited set of files without requiring an account. The official home of Regina, one of the free Unix interpreters. Archives of the messages in comp.lang.rexx and RexxLA messages are also maintained here. General Amiga archive.
Mailing lists are similar to newsgroups but use normal electronic mail to deliver the messages.
Ask your system administrator if you're not sure. Thanks to Scott Ophof for providing this summary.