I can speak to this specifically for the entertainment industry, specifically talent agencies.

Talent agencies have typically followed the apprenticeship model, and hiring non-agents to come in and represent clients is a relatively recent phenomenon that was not very common before the 1990s.

Mailrooms as the system of funneling new talent into an agency was pioneered by the William Morris Agency, which originally represented vaudeville performers. Abe Lastfogel, who went on to found WMA's West Coast office and eventually ran the entire agency, began as an office boy for William Morris. In the 1940's, WMA rebranded their mailroom positions as the "William Morris Agent Training Program", where hires were expected to start in the mailroom, rotate through different departments, and then be promoted to assistant or coordinator. WMA ceased hiring assistants and coordinators, and its junior roles were then filled by graduates of the training program.

WMA, as the dominant agency in the mid-twentieth century, also had many agents eventually leave to found their own agencies and they followed a similar model of having people start in the mailroom. Creative Artists Agency, ICM, and UTA all adopted similar training programs and most new hires were funneled through the mailroom rather than beginning as an assistant for a specific executive. The mailroom was often seen as badge of honor and a way to weed out people who would not be able to succeed in such a cut-throat business as Hollywood, and the major talent agencies to this day often recruit employees specifically to their mailroom programs.

Source: The Mailroom: Hollywood History from the Bottom Up by David Rensin

Hey all,

If you frequent the sub, you know the drill. If you're here from /r/all, or browse only occasionally, please be aware we have strict rules here intended to enforce the very high bar we expect from comments, so before posting, please read our rules. We remove comments which don't comply, and consider everyone forewarned. If you have feedback or commentary about how things are run here, please don't post it in this thread. We'll just remove it. We love to hear thoughtful, constructive feedback via the mail room however.

It can take time for an answer to show up, so we thank you for your patience. If you want to be reminded to come check back later, or simply find other great content to read while you wait, this thread provides a guide to a number of ways to do so, including the RemindMeBot- Click Here to Subscribe - or our Twitter.

Again though, please remember the rules, and keep them in mind while you browse. If you don't like how this subreddit is run, keep in mind that this method has seen us continue to succeed and grow for years, and isn't going to change, so at least try and make your complaint original. /r/AskHistory exists, so complaining about the rules to us is like going into a fancy restaurant to complain they don't sell chicken nuggets, even though Chick-fil-A is nextdoor.

---

As an additional, specific note, almost every comment so far removed has began "My mother-in-law" or "My friend's father". Our rules concerning personal anecdotes are clearly laid out, and this is not the appropriate venue for such responses. Published memoirs or diaries can form an important component of an answer to this question, but they also require careful reading and contextualization from secondary sources to be of use. If anyone is interested in the unverified first or second hand recollections from anonymous people on the internet, there is a subreddit for that, and I would recommend you post a similar question to this one on /r/AskReddit.