Ambien.

From Radar.com's exclusive story, Tila Tequila's Drug Problem: Snorting Ambien:

“She would base her entire day around it,” one insider told RadarOnline.com about Tila’s Ambien usage. “She would wake up, snort Ambien, Google herself, do more, Twitter all day and then sleep.”

Forgive me for getting all Charles Mudede on your asses, but the insider's second sentence tells us everything we need to know about Tila Tequila and the culture that made her a "star."

(Also, she's getting help for her Ambien-snorting problem on next season's Celebrity Rehab with Dr. Drew.)