Possible Clues:

• When repeated, a 'Seinfeld' expression
• When repeated, 'You get the idea'
• Blah alternative
• Tripled, a "Seinfeld" catchphrase
• 'Seinfeld' catchphrase, when tripled
• When said thrice, 'and so on'
• When tripled, 'and so on'
• When tripled, "and so on"
• When tripled, a "Seinfeld" catchphrase
• Part of a "Seinfeld" catchphrase