iSpot.tv, a startup that tracks national TV ads and correlates digital responses in real-time, said it has raised a $21.9 million B round led by Insight Venture Partners, with help from existing investor, Madrona Venture Group.

With the new round factored in, the three-year-old Seattle-based company has raised about $27.5 million so far.

Sean Muller, CEO of iSpot.tv, said the company will use the fresh funds to accelerate product development, add new capabilities to its TV ad measurement platform, and to expand its employee base, which is now at about 60, and expected to climb to 100 by the end of the year.

“We’re optimizing for growth,” Muller said, noting that iSpot.tv was cash-flow positive in the first quarter of 2015.

iSpot.tv’s platform uses real-time data to help its programming and brand partners monitor and modify their ad campaigns while they’re still in flight, tying in digital activity to help to determine and optimize the effectiveness of TV adverting.

iSpot.tv’s platform, for example, is designed to track how consumers react in the digital realm after a spot airs on regular TV. That additional measurement that occurs after the paid TV ad runs – something the company refers to as “earned digital activity” -- could include Google searches, replaying the ad on YouTube, or sharing or discussing the ad on social networks such as Twitter and Facebook.

“It’s getting more difficult to understand what you’re getting for your TV buys,” Muller said, noting that tracking that digital activity helps its partners determine the effectiveness of their TV campaigns and make adjustments on the fly.

While there are several companies that measure TV and digital activity, including Nielsen, Rentrak, comScore and Kantar Media (Kantar’s U.S. assets are now part of Rentrak), iSpot.tv is trying to differentiate by tracking measurement data at scale and in real-time.

Founded in 2012, iSpot.tv said it has more than 150 clients. Brands and programmers that work with the company include ESPN, The Walt Disney Studios, Sony Pictures, Paramount, Dish Network, NBCUniversal, American Express, Lincoln, Microsoft, Volvo, Sprint, and T-Mobile, among others.

Nielsen said it is renaming Online Campaign Ratings, its digital measurement product, with the new name Digital Ad Ratings, reflecting that the service also measures audiences using mobile devices such as smartphones and tablets in addition to computers. The service, launched in 2011, combines Nielsen TV and online panel data with aggregated, anonymous demographic information from participating online data providers to measure the effectiveness of television campaigns' extended to online ads. Nielsen said it has improved the service's user look and feel and has added in more demographic information from Experian and Nielsen. New data include estimated household income; race and ethnicity; family size and education level.

“The enhancements we’re making to Nielsen Digital Ad Ratings are about simplicity, and reflect Nielsen’s ability to grow and adapt our services to meet the needs of clients,” Megan Clarken, EVP, Global Product Leadership, Nielsen, said in a release. “As part of our ongoing effort to measure Total Audience, we will continue to evolve our offerings to provide the most accurate picture of the consumer, wherever, whenever and however they view content.”

As for the user interface enhancements, Nielsen said they include: "a dashboard displaying an overview of the client’s set of campaigns, including alerts and status (active and inactive), and dynamic, exportable charts and graphs built to match clients’ workflow and major analytic needs, in addition to the established data tables from existing Digital Ad Ratings campaign reporting." Searching campaigns by ID or name also have been made easier, Nielsen said.