As the media shifted to higher-capacity formats and with the ability for users to make their own copies of programs, the simple mail order method was threatened since one person could buy the game and then make copies for their friends. The shareware model of distribution emerged in the 1980s accepting that users would likely make copies freely and share these around. The shareware version of the software would be limited, and require payment to the developer to unlock the remaining features. This approach became popular with hobbyist games in the early 1990s, notably with the releases of "Wolfenstein 3D" and "ZZT", "indie" games from fledgling developers id Software and Tim Sweeney (later founder of Epic Games), respectively. Game magazines started to include shareware games on pack-in demo discs with each issue, and as with mail-order, companies arose that provided shareware sampler discs and served to help with shareware payment and redemption processing. Shareware remained a popular form of distribution even with availability of bulletin board systems and the Internet. By the 2000s, indie developers relied on the Internet as their primary distribution means as without a publisher, it was nearly impossible to stock an indie game at retail, the mail order concept having long since died out.