Posting revenue growth rates of more than 50% for the past few years, online printing company VistaPrint (NASDAQ:VPRT) is an anomaly in an industry that expands by only about 2% to 3% a year. And like other e-commerce companies that dominate their markets, including (NASDAQ:AMZN) and eBay (NASDAQ:EBAY), VistaPrint is aggressively reinvesting its profits because it expects the strong growth to continue for quite a while, even despite a recent sell-off in its shares.

In its second quarter, VistaPrint posted a 69% increase in revenues to $45.3 million. Net income was $5.6 million, or $0.12 per diluted share. That figure includes stock option expenses of $2.3 million, as well as a tax adjustment for $686,000. Excluding these charges, the company posted earnings of $7.2 million, or $0.16 per share. Cash flow from operations was $11.4 million in the quarter, with free cash flow totaling $2.5 million. The total cash in the bank is $108 million.

VistaPrint has a highly automated system that allows online users to design high-quality print products, such as brochures and business cards, and then routes the orders to large print facilities. It's a unique approach in the printing industry, and it involves investment in top programmers, engineers, and manufacturing experts. To protect its competitive advantage in this realm, VistaPrint has a portfolio of 11 patents and 40 more pending.

What's more, the company has invested significantly in building an efficient system to cost-effectively acquire customers. In the second quarter, it brought in 564,000 new customers to raise its total to more than 7 million.

Despite the growth, however, VistaPrint has seen its stock price fall from the mid-$30s to a little more than $22, as Highland Management Partners, one of the company's early venture capitalists, has sold more than 4 million shares since June. For a company the size of VistaPrint, with less than $1 billion in market capitalization, this is a significant move.

The selling, however, is not necessarily an indication of concern over the company's prospects. Venture capitalists typically liquidate their positions after a company goes public.

If anything, the dip in the stock looks like an opportunity, since VistaPrint appears poised to continue its rapid growth. The increase in new customers is a big positive, as is its continued launch of new products -- including self-inking stamps, notepads, and logo-creation software -- that will help it meet the needs of its growing customer base.

Moreover, VistaPrint plans to invest $14 million to $16 million in the next quarter in new facilities and equipment to meet future demand. Historically, the company has been able to turn its investments into five times as much in sales, so that a $14 million investment may translate into a capacity for $70 million in sales.

VistaPrint is bullish on its market, and it's investing now to make sure it can take as much of that market as it can. It's a good time to be bullish on the stock, too.

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Fool contributor Tom Taulli does not own shares of companies mentioned in this article.