- MOBI format was originally an extension of the PalmDOC format by adding certain HTML-like tags to the data. http://wiki.mobileread.com/wiki/MOBI
.mobi is the standard file extension for this format, but .prc is used instead in PalmOS, where only a limited range of extensions are supported.
This format has no connection to the .mobi top-level domain, intended for use on sites targeted at mobile devices.
References and format
Mobi is also a domain name: TLD .mobi