As part of its daily PR assault on the media Vonage sends out its subscriber number update. Using a 30-second-back of the envelope calculation technique I found that despite having only 115,000 subscribers the New Jersey-based company has in recent months hit a fast growth track. Its daily subscriber sign-ons have almost doubled from (nearly) a year ago. Between February 2, 2004 and March 1, 2004, Vonage was adding about 555 new customers every day. Rest of the data in this graphic. This is clearly not scientific data, but still gives you an idea.