High Quality Content by WIKIPEDIA articles! Squish is both the name of a FidoNet mail tossing application originally designed for DOS and OS/2, and the name of the primary mail storage format in which this application stores FidoNet and other local BBS messages. Before Squish, open storage formats for FidoNet and Bulletin Board messages were relatively slow and inefficient. The primary functions of the Squish application in a FidoNet system are to: