It follows from Goldman Sachs Greg Smith doing exactly the same.
When someone leaves, they're inclined to tell the world and it appears on Social Media.
But did you expect it from an Irishman abroad?
I don't know him - I don't think I do anyway - but meet Irish senior Outdoor Advertising man Jerry Comyn who's left US major outdoor player 'Titan' (he's from Navan so he worked in Ireland too with Nova and gives Ireland a good old mention) and decided to tell all in an email letter to his contacts after 18 years in the business. (Within hours of publishing it, I heard from the man himself and publish his comments at the end).

He says it's not a reflection on any one company but just his general advertising experience.

It's all over the web so I've no reason to doubt it's true.

And Twitter? Nearly all the responses (and there's masses of them) are thumbs up. 
Plenty of "me too!", "Go Jerry Go!" and even one spuriously claiming that "his life in advertising sales brought him a life of debauchery".

Now him, I do know. 
And I'm desperately trying to make contact.

Jerry is on LinkedIn (to be fair, his resume reads real well).
In fact he's on everything.

You'll find him on Facebook - without any difficulty!
I'd say at this stage if you just Googled 'Jerry', you'd get only 2 results - him and Tom Cruise.

The letter is reproduced courtesy of Business Insider. So let that be a warning. It'll get out.
And the other warning - don't write something on the spur of the moment you might regret. Leave it and think on it overnight, then send it. Most don't on reflection (it's an old business rule).

Anyway here goes:
“Hello all,
Having spent the past 18 years of my life in advertising sales, TV, Radio and Outdoor, I’ve always wondered why I was in a business I detested. For years, I couldn’t figure it out, and then I realized what was motivating me, MONEY! There are few careers where one (we called ourselves a business of C students) could earn so much money for doing very little.
The hardest I ever worked were the first 5 years of my career, from 1994 to 1999. This is mostly because I spent my days making my boss look good. I earned him/them a lot of money by making sure the media buyers were kept happy. Let me tell you, back in the mid 90′s, NYC buyers were animals. If you weren’t at the top of your game, they would eat you without salt. As a result, I believe, I learned ‘the business’ from the best.
Over the years I learned that I was part of a ‘club’ I had no desire to be a member of. By the mid 2000′s I found myself lashing out at the very corporate system I had signed up for. Had I sold my soul? No, there was no way I could have done that. Alas, I realised I had indeed sold my soul for the almighty dollar.
Recently, I decided, once and for all, to leave the industry I have dedicated the last 18 years of my life. The reasons are numerous but following are a few:
* I was trained to lie to clients and cheat as much as possible.
* I was encouraged to dismiss FCC regulations on clients business.
* 99% of Advertising Sales Reps spend their days figuring ways to rip off clients
* 99% of Advertising Sales Managers got their positions by lying and stealing their way to the top.
* Most competing TV and Radio Stations COLLUDE on rates.
* Most vendors are ripping off clients by up to 80%
* Reps WILL rip off their bosses (through expenses) if you treat them like crap.
* Most reps are managed through fear, the worst motivator, in my opinion.
* There are few leaders left in a business that once promoted leadership
I know most of you will think these are the bitter words of a disillusioned ex-rep. Maybe you’re correct, but I like to to think of my words as coming from someone who is finally calling BULLSHIT on the ad sales world, both in the USA and Ireland.
I wish you all good fortune and good luck.
Collusion on rates Jerry? You're kidding.
Can't be true. Nah. Could it?
Letters in a stamped addressed envelope please.
(Since publishing last night, I heard from Jerry this morning - "Hi Stuart...thanks for your commentary on my letter. I never expected it would go viral but I guess it touched a nerve with many people. 
I should also like to clarify that I gave very serious consideration before sending the email, which just happened to go viral. With regard to 'collusion' on rates, that is a federal offence in the USA as controlled by the FCC")

Funny enough he sounds like a completely rational bloke to me.