Why is it that in the US potential employers can find out whether or not you have been arrested? In the UK, you only have to disclose your dealings with the law if you’ve either accepted a police caution (i.e. owned up to an offence) or been convicted by a magistrate or a jury. Merely being arrested isn’t good enough. How is it even constitutional to be punished for a crime for which you haven’t even been charged, never mind convicted?
It's called Google. That and the burgeoning mugshot blackmail industry.
Basically, you obtain public records of mugshots and arrest records from around the country, post them on your website, and then charge fees to anyone who wants their arrest records removed.