IVR and VoIP provider Voxeo has been putting up annual growth numbers near 100%, serving dozens of big name companies, and getting considerable attention from VC’s in the Valley as of late. However, the company has remained largely under the radar since its founding in 2000, and has done so deliberately. CEO Jonathan Taylor explained to us how keeping a low profile while doing high volume business has been easy in this particular industry.

In short, Voxeo does its job so well that its clients don’t talk about it. When an enterprise discovers their platform they keep it a secret to preserve the competitive advantage. As a result, Voxeo doesn’t even publish a list of notable customers. Relationships with clients have been so discreet that many of their customers are listed as competitors in market research briefs.

The company continues to grow at an impressive rate, and has recently expanded into foreign markets and started acquiring smaller companies. Taylor says they are being approached by several VC firms, but will most likely not announce anything until late September. It will be interesting to see how much longer Voxeo maintains its underground profile. Based on BT’s valuation of Ribbit, they could be worth a whole lot of money.