Most graphics software only opens one or a few types of graphic formats. See file formats by Eric Perlman and Ian Kallen. See GeoCities for free personal web site space. ISPs use standard Internet software and communication protocols. Or check Network USA's list of IPSs in your area .
Information is narrow cast only to the subscribers.
Apple's dial-up software for older Macs. See MacPPP . Replaced by FreePPP . See MacTCP . 14.4k and 28.8k baud modems are becoming standard.