Google raised ad prices incrementally through internal “pricing knobs” that advertisers couldn’t detect, according to federal court documents.

• Google raised ad prices 5-15% at a time using “pricing knobs” that made increases look like normal auction fluctuations.
  
  
• Google’s surveys showed advertisers noticed higher costs but didn’t realize Google was causing the increases.
• A federal judge now requires Google to publicly disclose auction changes that could raise advertiser costs.