ScanScout, an online advertising network that places ads in contextually relevant video content, just brought in $5.1 million of an anticipated $8.1 million third round of financing, according to PE Hub. Based in Cambridge, Mass., the company’s backers include General Catalyst Partners, Time Warner, First Round Capital and famed Silicon Valley investor Ron Conway.

ScanScout last raised funding in May 2007, bringing in $7 million. Created by two MIT graduates, it was initially seeded in 2005 by First Round, former Googler Georges Harik and Conway.