Spinning this one off a mention in "XPT's 100 Ugliest Girls" from 2007.

My vote is for when "Vivid Contract Girl" became synonymous with performing the barest minimum of a sex act in a movie filled with "high-budget" tactics such as slow motion, Vaseline-smeared lenses, obscuring soundtracks, condoms, etc.

Other possibilities include:

Andrew Blake.
John Stagliano/Seymour Butts/"gonzo"/Max Hardcore
AIDS/HIV first identified.
The Internet.
The Meese Commission, and the ensuing Traci Lords firestorm.
Belladonna.