This is 99% invisible.

I'm Roman Mars.

When you send a letter to the President,

it first passes through the Office of Presidential Correspondence.

The office was started under President McKinley in 1897 who had been receiving about 100 letters per day.

By the time Herbert Hoover was president, that number had gone up to about 800 letters per day.

Today, the President of the United States gets tens of thousands of letters, parcels, and emails every day.

That President, as we produce this story, is still Barack Obama. That president.

We're Mr. President. Dear Mr. President.

We met once.

You came to my hometown of Tuscadis, Alabama in regards to our relationship with Canada.

And if you're one of those letter writers, you must imagine that the odds of the president

actually reading your letter are pretty slim.

That's Jacob Brogan a writer for slate.com and host of working a slate podcast.

And you'd be right those chances are pretty slim.

People often begin with a reflection on,

I know no one will read this.

I mean that is a really common open.

But someone does read your letter or email,

and sometimes that person is Fiona Reeves,

Director of Presidential Correspondence at the White House.

We are the office that handles all the incoming correspondence

...