SEASEA stands for self-extracting archive. It is the extension given to some Macintosh files which have been converted from a binary format to an ASCII (text) format. Files are served to the Internet in this format in order to allow users to send them via electronic mail and to send or receive them over an FTP program. Files converted from binary to the ASCII format have been compressed, and they normally appear in what is called a software archive. The files in the archive are called archived files.
Files which are available for transmission on the Internet normally end with an extension. These small packets of letters provide a lot of information, so it's a good idea to take a few minutes to learn what they're telling you about the file of your choice. They signal an archived file which a user can download to her desktop. PCs, Macintoshes, and UNIX files end in different extensions. Examples of DOS archive extensions are: .arc, .arj, .lbr, .lzh, .zip, .zoo. UNIX extensions include .Z, and common Macintosh archive extensions are: .cpt, .sea, .sit, and .hqx.
It is important to pay attention to the type of archived file you are dealing with, as each extension requires a different method of extracting (decompressing). The .sea extension is the friendliest of all for Macintosh users, as it does not require a helper application to open it -- hence the name, self-extracting. To extract a .sea file, the user need only double-click the file after it has been retrieved. If this sounds too good to be true, it almost is. The added convenience of the self extracting file makes it a likely virus transmitter. For this reason, it is often wise to take a little more time to download a utility to decompress one of the more predictable archive types. .SEA is also found as an extension on a file compressed in a different format, like .hqx, for example. In this case, it is used as an installer (it installs the program being downloaded).