A crack intro, also known as a cracktro, loader, or just intro, is a small introduction sequence added to cracked software, designed to inform the user of which "cracking crew" or individual cracker was responsible for removing the software's copy protection and distributing the crack. Many people who did the actual cracking did this competitively. They even credited themselves alongside the software publisher's name in their custom cracktro screens. Warez groups began to add their own intros instead of modifying the existing loading screen. Names of the group's members would scroll as little animations. Intros became more complicated and sometimes as large as the game itself. It had to look good to impress viewers as well as peers, and sometimes the result was more impressive than the game itself. They first appeared on Apple II computer in the late 1970s, early 1980s. The early text screens are in many ways similar to graffiti, although they invaded the private sphere and not the public space. In 1985 the Dutch teams The 1001 Crew, programmers from the city of Alkmaar, and The Judges started adding intro demos, challenging others to match theirs. Dozens of demo crews formed within a year to try and do just that.
These first appeared on ZX Spectrum, Commodore 64 and Amstrad CPC games that were distributed around the world via Bulletin Board Systems (BBSes) and floppy disk copying. Initially the intros consisted of simple messages, but they grew progressively more complex as they became a medium to demonstrate the purported superiority of a cracking group. Even the commercially available ISEPIC cartridge, which produced memory dumps of copy-protected Commodore 64 software, added a custom crack intro to the snapshots it produced.
Crack intros became more sophisticated on more advanced systems such as the Commodore Amiga and Atari ST, as well as some IBM PC clone systems with sound cards.
As a result, crack intros began to feature big colourful effects, music, and scrollers. Cracking groups would use the intros not just to gain credit for cracking, but to advertise their BBSes, greet friends, and give themselves recognition. Messages were frequently of a vulgar nature, and on some occasions made threats of violence against software companies or the members of some rival crack group.
Crack intro programming eventually became an art form in its own right, and people started coding intros without attaching them to a crack just to show off how well they could program. This evolved into the demoscene.
Crack intros that use chiptunes live on today in the form of background music for small programs intended to remove the software protection on commercial and shareware software that has limited or dumbed-down capabilities. Sometimes this is simply in the form of a program that generates a software package's serial number, usually referred to as a keygen. These chiptunes are now still accessible as downloadable musicdisks or musicpacks.