The vacations are over. Back-to-school sales have come and gone, while big yellow buses rejoin the fray that is my morning commute. Talk of football fills the airwaves and Facebook feeds, letting us know that fall is (almost) here.

For me, the annual September release of Inc. magazine’s top 500 private companies (stretched to 5000 online) has been an autumn rite for as long as I can remember.

For the uninitiated, Inc.’s list is ranked by the percentage of revenue growth over a three-and-a-half year period by privately held, for-profit independent companies that meet some qualifying financial requirements. Some companies appear on the list briefly before going public. Other companies are stalwarts, like North Carolina software maker SAS, which has appeared on the list each year since 1981.

At Feedback, we’re frequently charged with surveying the social media landscape of entire industries, clients and competitors alike, to evaluate the overall usage and uncover best practices. For the purpose of this post, I thought I might do a quick audit of this year’s Inc. 500 No. 1 fastest growing company, ideeli.

If by chance you haven’t heard of ideeli, you’re certainly familiar with the concept: a members-only online retailer, a “Flash-shopping” site, with regular-if-not-daily emails offering merchandise for greatly discounted prices. While ideeli counts sites like Gilt Groupe, Rue La La and HauteLook among its main competitors, it’s a short leap to their much-ballyhooed geo-specific daily deal siblings, Groupon and LivingSocial. Most of ideeli’s thousand brand partners are in the fashion world, though offers for such things as travel present growth opportunities they are just beginning to explore.

So how is a company of this size and potential using social? At first glance, the answer is quite well.

On Facebook, multiple daily posts reflect their assets via pictures, as well as their sponsors and items of general interest to their more than 170,000 fans. Likes by the hundred and comments by the dozen are common within hours of posting.

The effort on Twitter is strong as well. Having cultivated a base of almost 26,000 followers with over 20,000 tweets since September 2008, the content and interactions really flow here. Chances are if you direct your message to @ideeli, you’ll get a personal response. At the time of this writing, there were twenty direct responses to individuals tweeting their questions or affections for this shopaholic’s dream.

In addition to their regular offerings, they also do what they call “Flash Friday” giveaways for an unspecified and far briefer time period that you can only participate in by following on Twitter and using the appropriate hashtag in your messages. Clearly, there is some serious social media savvy within the company’s Manhattan headquarters.

As a business that contacts its consumers regularly via email, you could give ideeli a pass if they failed to make use of a blog along side their other efforts. However, the clean design and presentation of information, as well as the availability of multiple RSS feeds at blog.ideeli.com provide a strong complement to the other promotional efforts, though it would seem with less traffic and far fewer interactions. I am somewhat surprised – given the adoption of Tumblr within the fashion community – that ideeli has not embraced that site and its potential to further engage with its clientele. A presumptive search for ideeli.tumblr.com gets forwarded back to the main site, where an unformatted page lies begging for completion and content (I know some who would be willing to help them out with that).

I’m somewhat obsessed with deal websites, so I was surprised to see a site that I had never heard of (though competitors Gilt & Rue were on my radar) top the Inc. 500. Who knows where they will place on next year’s list: Maybe they’ll go public or be bought out and no longer qualify. Or maybe they’ll find a goldmine in other retail sectors and continue to grow at this torrid pace.

Either way, I’m sure they’ll be keeping up with their strong efforts in social. If you’re looking for an example of a private company doing it right, look no further: ideeli’s the real deal.

-Thomas (@thomasmcdonald)