Mobile engagement platform SessionM is building out its business and adding executives.

Gerald Hewes leaves Apple's iAd division where he led the analytics, optimisation and insight team, joining SessionM as VP of engineering.

Amy Jerusalmi also leaves from iAd, and prior to that was at Quattro Wireless. She joins as VP of client services.

Both Hewes and Jerusalmi will be well known to the SessionM team, as it was founded by key executives from Quattro, which was acquired by Apple in 2010.

They went on to create the iAd business.

Deborah Powsner has a different route into the company where she takes the role of senior director of marketing. Powsner was previously responsible for business marketing and insight for the Google+ platform.

Onwards, upwards

These hires come on the back of SessionM's $20 million B Series funding round.

The company, which is now over 40 people strong and has offices in Los Angeles, New York and San Francisco - as well as its Boston HQ - includes clients such as Volvo, Unilever, Honda, The Weather Channel and Viacom Interactive.

"In order for developers and advertisers to engage and retain mobile users, they need a new approach and that's exactly what we deliver," said Lars Albright, SessionM's co-founder and CEO.

"We're redefining mobile engagement, and I couldn't be more excited about the team we're building to meet this challenge."

[source: SessionM (PDF)]