It is also the primary facility for publishing files to a web server. This refers to a derogatory e-mail message. Such messages are considered to be poor net-etiquette. This is the protocol which enables the communications between a web browser and a web server. It is the physical means by which you inter-connect your computers, printers and other devices.
Attachments are usually word processing files or spreadsheets.
FTP should be used for any files which are 500K in size. A block of transmitted data. Several packets make up a typical transmission. This affords such users a high level of privacy for all communications. This is typically the location where the ISP's modems live.