 The font files are made small by use of subsetting (only including the needed characters), and only need to be downloaded once.It is a secure method, in that fonts can only be used for the pages they were intended for, and not on other sites, or in other applications.TrueDoc was natively supported in Netscape Navigator 4, but was discontinued in Netscape Navigator 6 and Mozilla because Netscape could not release Bitstream's source code.