Version 2.0 was the first version to circulate widely. Adobe realized that for PDF to succeed, the reader had to be free. In a radical move, Adobe began distributing for free on CD-ROMs and floppy disks.
A major turning point occurred when Adobe began distributing Reader for free, which eventually helped PDF become the de facto standard for fixed-format documents. Version 3.0 to 5.0: versions of adobe reader