The network, which has carried the series on-air for years, has four episodes available (including the famed "Yada Yada" one) on TBS.com and plans to offer several at a time on a rotating basis. It's unclear whether streaming rights are part of a renewal of Turner's syndication deal with Sony Pictures Television or an amendment to an existing agreement.

Pre-roll spots for the episodes are being sold as part of a package covering multiple video offerings across TBS.com. That inventory includes episodes of syndicated "Family Guy" as well as TBS series "My Boys" and "Tyler Perry's House of Payne."

Turner has been aggressive at looking to drive traffic and ad dollars by streaming full episodes on its TBS and TNT Web sites.

The "DramaVision" section of TNT.tv offers episodes from former WB series "Charmed" and has carried the TNT hit "The Closer."

And Turner's deal with NBC Universal regarding "The Office" on TBS allows it to stream episodes starting in the fall of 2009.

While episodes of "Family Guy" and "The Office" are available elsewhere on the Web, TBS.com appears to be the only legal locale for "Seinfeld."

Industry-wide, there are varying theories as to what ratio of ads for streamed episodes will be sold in scatter vis-à-vis the upfront, but it appears the upfront is expected to be an increasingly active marketplace in that area.

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