Possible Clues:

• Park — -joon of "The Marvels"
• Google rankings metric: Abbr
• "The Marvels" actor Park __-joon
• Online marketing metric, for short
• Concern for online advertisers, for short
• Marketing process hidden in 'mouse over'
• Metric for online traffic, in brief
• Term that explains a great deal of the nonsense on the modern Internet