Update III: Vonage shares closed down $2.15 at $14.85 on volume of 33.8 million shares.
Update II: Vonage shares have dropped by $2.50 to $14.50 in active trading - perhaps justifying the views of critics who questioned how a money-losing compoany in an ultra competitive business could value itself at $2.5-billion. Still, it is surprisingly to see Vonage tumble so much given investment bankers are supposed to "leave money on the table" for IPO investors.

So the Vonage IPO has been priced at $17 a share, which will bring in IPO proceeds of  $531-million. Any bets on where this baby closes after its first day on the NYSE? My guess is up, way up as retail investors pile into the game. After that, it really hinges on Vonage's quarterly results over the next year. If the company's expensive marketing bonanza isn't offset by strong gains in subscribers, watch out! If, however, Vonage's financials show signs of improvement, it could incite investors to jump onboard. That said, Vonage is facing intense competition from cablecos, carriers, Skype, etc.. This means it can't pull back on the marketing engine to boost the bottom line. At the end of the day, the corporate "strategy" may be to attract enough customers to solicit a takeover bid. If anything, Jeff Citron (who has already hit two entrepreneurial "home runs" with Datek and The Island ECN) is super-savvy so the IPO may be part of his Vonage master plan, which has already made him more than $800 million - at least on paper.
Update: Entrepreneurship Blog suggests Vonage could go through its IPO proceeds of $531-million in 7.5 quarters given its burn rate. That's asssuming, of course, the company doesn't attract any more customers. Meanwhile, The Tech Beat questions why investors are more excited about the Vonage IPO than that of MasterCard, which made $319-million in the past 12 months.