Did you hear about the "green" startup that touted how environmentally conscious it was by sending reporters five identical copies of its press kit, each one filled with nonrecyclable package "popcorn" and a small forest's worth of paper? Needless to say, the startup didn't get any press coverage.

In the era of social media, you may think public relations doesn't play a role in your marketing plans. Think again. In fact, thanks to social media, committing PR blunders can sink your startup even faster than ever, no matter if you're selling the coolest products or offering killer services. To make sure that doesn't happen to your company, we asked marketing maven Gini Dietrich to share six regrettably common PR mistakes today's startups must avoid.

Dietrich - founder and CEO of Arment Dietrich, an integrated marketing communication firm, and author of the PR and marketing blog Spin Sucks - knows there's a fine line between creating a brilliant PR strategy and one that can blow up in your face.

To make sure you end up on the right side of that line, avoid trying to do it yourself - and these all-to-common errors:

1. Not making PR a priority. Many startups think about PR last, as if it takes only two months to launch your business to the world. In most cases, you should bring on PR help at least a year before you launch, but no later than six months prior. If you wait until you're ready to launch, no one will know about it for a good three to four months after you're out of the gate -- and in today's world, that may be too late to do you any good.

2. Hiring a PR firm without thinking about the ROI. Startup founders tend to relate public relations to publicity and hire a PR firm without any idea of how they're going to measure results, other than the number of stories placed. While publicity is one tool PR pros use, it's not the only one. Don't hire a PR firm just to get stories about your startup in your targeted blogs, trade magazines and other media. Hire a PR firm to help you drive sales, and ask them to show you how their efforts will do exactly that.

3. Abdicating all responsibility to the PR team. PR is a joint effort. You have to put in time-building relationships. Don't expect that just because a PR firm already has connections with the influencers you need to reach, it can sprinkle some fairy dust and get you in front of the right people in a matter of days.

4. Flying by the seat of your pants. You need to develop a strategy with your PR pros to get your messaging exactly right. (This heads off mistakes like boasting about being green in the least eco-friendly way.) When criticism or negative comments about your business arise (and they will), you need to be prepared with an immediate response in our 24/7/365 world. At the very least, have an informal crisis plan at-the-ready that includes the five Ps: Predict, Position, Prevent, Plan and Persevere.

5. Being inflexible. Your business is your baby. Everything about it is glorious to you. But a PR professional will know how to tell your story in a way that gains traction, explains the brand and scales your business. If you aren't willing to adjust the story in your head, you may fail at telling the story your customers want to hear.

6. Refusing to listen to criticism, advice and feedback. Social media has revolutionized how businesses get feedback about their efforts. But you must be willing to listen and incorporate what you see and hear. An outside PR professional (or firm) can be essential in helping you listen, monitor and absorb.