Viral video tracking and measurement firm Visible Measures has closed a $10 million series C round of funding, led by Northgate Capital. Existing investors Mohr Davidow and General Catalyst also participated, bringing the total capital the company has raised since launch to $29 million. The last time it raised money was in January, 2008.

Visible Measures lets both ad agencies and big video publishing sites on the Web track viewership and engagement with videos across the Web. Ad agencies can measure the effectiveness of specific video ad campaigns, and publishers can see which of their videos are being played and passed around the most.

The company is currently tracking more than 200 million different online videos and video ads. Each day it measures the equivalent of 100 years worth of collective online video viewing consumption. It is trying to bring the types of metrics normally associated with direct response ads to brand awareness.