Tommy Kearns has been building businesses for two decades.  The chief executive of Xtremepush, a fast-growing and heavily-backed digital marketing company, Kearns has positioned himself and the business to be in a prime place for the death of third-party cookies in 2024 and a new era of the internet which is intended to be permission-led and privacy-focused. Founded in 2014 by Kearns, his brother-in-law, Padraig Shanley, and Kevin Collins, who is chief technology officer, Xtremepush is growing 30 per cent year-on-year through a cocmbination of organic growth and acquisition and has raised $41 million in debt and equity, in two…