Adobe Acrobat is a family of application software and web services developed by Adobe Systems to view, create, manipulate, print and manage files in Portable Document Format (PDF). The family comprises Reader (formerly Acrobat Reader), Acrobat (formerly Acrobat Exchange) and Acrobat.com. The freeware Adobe Reader, available for several desktop and mobile platforms, can view, print and annotate PDF files. The commercial proprietary Acrobat, available for Windows and OS X only, can also create, edit, convert, digitally sign, encrypt, export and publish PDF files. Acrobat.com complements the family with a variety of enterprise content management and file hosting services. Since the early 1990s, the Acrobat product has had several competitors, some of which used their own document formats, such as: By the late 1990s PDF had become the de facto standard. This has resulted in the development of both free and commercial programs that create or manipulate PDF. Adobe also allows Acrobat plug-in...