Adobe Systems Inc. is the company that developed PostScript, many fonts, and recently has acquired Aldus. Since PostScript is no longer portable, and lacks many features necessary for document interchange, they have developed the Acrobat line of software.
The Acrobat tools are based upon PDF, their new Portable Document Format, which not only includes page images, but also thumbnail sketches, table of contents, hypertext links, and other components such as SGML.
One can distill PostScript documents into PDF. With Exchange, one can merge files, add links, and make annotations. Anyone can obtain a free copy of Reader to access PDF these files. Recent enhancements allow Reader to be launched from Mosaic, and for links in PDF files to lead to other documents on WWW.