This video has been making the rounds. It addresses a pervasive problem in the advertising industry. When pitching new business, agencies are often expected to supply not just concepts but fully fleshed out campaigns which require hours of labor and can cost tens of thousands of dollars to produce. That's a lot of work for a client who may not even hire them. On top of that the speculative client can demand the rights to the intellectual property that the agency has created. Basically agencies are giving would-be clients millions of dollars in work for free hoping that they are awarded the account. 
This is what's called speculative (spec) work.
Agencies aren't the only ones facing this problem. Talk to any freelancer or vendor and they'll have stories about being asked to do free work too. Sometimes it's for pro bono clients like non-profits and charity groups, and that work can be rewarding and extremely creative. My own short documentary "Bryce's Story" was just that sort of project. Spec is a different animal completely. Spec is work that you should be getting paid for. Whether a photographer, designer, stylist, director, post house, or composer, most of us have been asked to provide free labor on the possibility of more work down the road.

There are no bad guys here. Budgets are getting smaller all the time it seems. Agencies are being asked to provide more content more quickly to feed the gaping maw that is social media. I get it. But agencies still have to make payroll and keep the lights on. We freelancers still have to eat and pay our rent. And we all still want to do amazing work for our clients. We just think we should be fairly compensated for doing so. 

So I applaud Zulu Alpha Kilo, other agencies, and legions of freelancers for taking this stand and I hope that when they say "It's time we all said no to spec" that that sentiment extends to all of us in the industry. Because no one likes being asked to work for free.