In a sign that online video is the future of media, Tremor Media announced that it raised $18 million in Series C financing, for a total of $37.6 million in funding.

Leading the round was Meritech Capital Partners, with participation from Tremor Media's existing investors, such as Canaan Parnters, Masthead Venture Partners, and European Founders Fund.

The round follows the company's third straight year of triple-digit revenue growth, according to the NY-based company.

As an online video publisher seeking higher and higher CPMs and a broader advertising footprint, I'm highly interested in this company. Tremor Media competes with other video advertising companies, such as Adap.tv (our current video ad provider) and Ooyala (emerging video ad network and platform). 

Tremor Media tells its potential publishing clients that it can get between $7 and $13 effective CPMs for its customers. That's a very healthy rate, but it also requires that pre-rolls and mid-rolls play on the video. Unfortunately, those video advertisements are a minimum of 15 seconds long. Tremor Media is also integrated with other advertising networks, such as ScanScout and Google, to name a few. A publisher has to create a separate relationship with each of those networks, but has the option of inserting ads from those networks, should they be higher than the ones Tremor Media provides.

Unlike Ooyala, Tremor Media does not provide bandwidth, analytics and syndication. But Tremor does provide its owner video player, should a publisher be in need of one. 

Tremor Media has the fourth largest video ad network, behind YouTube, MySpace and Yahoo, according to comScore's video metrix.

Tremor raised $11 million in January 2008, and  $8.64 million in September 2006.