Jeff Bezos famously declared: “Your brand is what other people say about you when you’re not in the room.”

But where do you begin the brand building process when you’re a startup? Most founders believe that marketing is something they will do when “they can afford it.” The problem with “being ready” for marketing is that it’s a lot like getting ready to have a baby. There’s never a good time to have one, and there’s always a reason you can’t.

I’ve often wondered why entrepreneurs believe that marketing works for established companies but not for emerging ones. And if that’s true, how do little companies ever become bigger ones?

The problem may be that founders are asking the wrong question. It’s not “when you’ll be ready for marketing” but “what you need to do now,” so you’ll be ready for marketing when it’s time to scale your business. Traditional marketing doesn’t work for startups because they haven’t yet built a proven track record and are still trying to identify who they are and whom that might matter to. Steve Blank, the highly successful Silicon Valley serial entrepreneur, and the man who launched the Lean Startup Movement, puts it simply and eloquently: “Startups are not just a smaller version of a larger company” but an entirely new kind of system. According to Blank, a traditional business plan will be obsolete within six months and that’s why a lean version is needed to get a new business off the ground. The same idea applies to “lean marketing.”

Traditional marketing requires a significant investment that most startups simply don’t have. Anyone who’s ever considered running a TV spot during the Super Bowl understands how prohibitive advertising can be; and unless you have $100,000 a year to spend, media buys are a waste of money for a startup. Remember, it takes on average, seven times to become aware of an ad and that’s before you’ve even read it. It’s a numbers game that only established brands can afford to play.

There’s also what I call the “Holy Grail” of marketing—the elusive “word-of-mouth” referral—and with it, the belief that your customers will sell your product or service because they can’t wait to tell everyone about it and as a result, you don’t need any kind of marketing at all. The trouble with a “word-of-mouth” strategy is that you still need relevant messaging that delivers your value proposition quickly and effectively to potential customers so that early adopters can help bring more traffic to your digital door.

“Lean marketing” focuses primarily on identifying those early adopters, establishing a differentiated value proposition and coming up with a pithy elevator pitch and relevant content. The metric to use is simple: Does my lean marketing strategy create brand awareness? Once you have your messaging in place, social media is a great and inexpensive way to get people excited about engaging with your brand.

For those of you who consider social media irrelevant, it’s important to remember that there are roughly 2.1 billion people on social media every month, and 1.5 billion are on Facebook alone. So why is it that social media is so often relegated to an intern’s “fun” job? During the first couple of years, it’s the founder who should be writing content or working with a professional copywriter to make sure that they are telling their authentic story. Your intern can then make sure that your social media feeds are getting fed on a regular basis. Founder stories make great PR and help build credibility quickly, which is key to growth because credibility helps build trust which helps build brand awareness and loyalty.

It’s also good to remember that to be successful, traditional marketing requires an investment of a minimum of 20% of gross revenues (not a typo) and even established companies rarely spend more than 5%.

So instead of waiting to start with traditional marketing, consider using the tools in your “lean marketing” toolbox. Start with your vision, why you decided to start your business in the first place, and identify the social media channels you want to use to tell your story. And most importantly, keep it small and manageable. There are currently more than 500 social media sites and that list is growing. That’s why identifying your key customers is so critical. Find out which sites your customers spend time on and go there so you can learn what’s important to them. Get to know top bloggers in your industry and follow them. Get involved in conversations where you can demonstrate your expertise and build a fan base.

Remember that the longer you wait, the harder it will be to build traction, and in the meantime, you’re not building your marketing funnel—the very people you’re hoping will become your next customers.