eMail Servers (Mail Transfer Agent: MTA)
Note: How to open graphic files attached to an email from a MAC user when you are on AOL.
Why people get winmail.dat attachements
MS Exchange sends it's e-mail as an RTF file to other MS Exchange clients so the original formatting can be viewed by the recipient. However, when MS Exchange sends the e-mail message to non MS Exchange mail clients it sends the file as a normal text only document (read: industry standard) and as a binary encoded attachment (winmail.dat) also containing any data files attached to the email that can be decoded (see http://www.fentun.com/) and viewed as an RTF document in a Windows (or MacIntosh) word processor or other program.
If someone is using MS Exchange (or perhaps even MS Internet Explorer) for EITHER the PC or MacIntosh to send e-mail to this list they may be INADVERTENTLY sending the winmail.dat attachment too. This could be done with a PC or MacIntosh. It's not platform specific. A user can configure MS Exchange to disable the winmail.dat feature to everyone on their e-mail list or to a select few.