An understanding of the challenges faced on each side of the divide and the ability to communicate across it remain at the heart of smart PR practice.
But now, I wonder if the lines between the two are not becoming too blurred, with the professional dialectic being eroded by the fusing of the two disciplines.
The crossing from one to the other (almost inevitably from journalism to PR) is a well-established trend and a path that I trod a dozen years ago. Jonathan Oliver, an accomplished journalist, has just become the latest Sunday Times political editor to make the switch. I have no doubt he will be a huge success.
But what is now emerging is a growing group of professionals seeking work on both sides of the divide. Days of mass redundancies and hardship in journalism are spawning a growing band of crossover practitioners who seek to milk the proverbial cow at both ends by switching allegiance on a daily basis.
Many local news agencies now offer PR services to clients as well as stories to newspapers. Can they really put hand on heart and say there is never a conflict between providing a story to a media outlet on a commercial basis and the best interests of clients?
Last week in the eye of a media storm around two of my clients, I received the usual kind offers of advice from fellow professionals. I was particularly grateful for the daily flow of media comments containing the wisdom of Messrs Clifford and Borkowski - the Borky and Max show, as it was dubbed in my office.
Among others was a thoughtful note from a sassy and experienced tabloid journalist who was combining a short-term role as a newspaper executive with that of running a sole-trader PR business.
The advice offered was not entirely without merit. But whose best interests was it intended to serve?
Both journalism and PR are hard taskmasters. Knowledge, experience, contacts and creativity are valuable and transferable skills. But surely their owners can serve only one master?
Ian Monk is founder of Ian Monk Associates and a former executive at the Daily Mail and The Sun