Ad tech company Integral Ad Science has announced a $30m Series D round of funding, which CEO Scott Knoll says will help the company expand globally, as well as tackle mobile advertising.

To date, Integral has specialised in assessing in real-time the quality of traffic for online display ads, with a video viewability product added at the end of 2013.  They are already working with half of the Fortune 100 globally – both ad buyers and sellers – to help them understand their ad placements, answering questions like how many times has the ad been seen? and is the traffic human?

“Were helping companies understand what they should and shouldn’t buy and how much they should pay – whether thats display, video, and soon to be mobile,” Knoll said. “Mobile is strategically important  – we recognise that – and part of raise was to focus on that.”

The companys data science team was originally tasked with creating tech to solve wrong page issues but bots have become an increasingly big problem. Knoll says that up to around 20 to 30 per cent of traffic currently comes from non-human sources. “This is a continuation of click fraud, something that the industry spent a lot of time clearing up. This has now moved to impression fraud and until recently it went largely unnoticed but a large percentage of traffic isnt real.”

Knoll says that generally brands have been so focused on targeting users that they don’t always differentiate quality, a criticism that could also be levelled at the murky incentivised download market in the app stores. “Anecdotally we hear ad fraud is a problem on mobile – as soon as there is money to be made, there will be fraudsters focusing on how to take advantage of that,” he said.

Integrals fastest growing business area is real-time bidding, which goes hand in hand with the companys mobile push. “When we start collecting mobile data, we will build a product that can enable pre-bid segmentation for anyone doing RTB on mobile ads. We’re a way off from getting there yet but that is certainly where the market needs to go – targeting the user regardless of where they are and understanding the relative opportunities to do that.”

The company opened its first international office in London in February last year and Knoll said that further countries in EMEA, plus a new presence in APAC, are also on the cards in 2014.