As I explained two weeks ago, this thing is the anti-Google.
Vonage has a decent product, but they're losing shiploads of money every quarter while Google rakes in massive margins; Vonage founder Citron has a blemished reputation while Google's executive team is clean and the brand (used to be) squeaky clean; Vonage's high-priced product is competing in field of free alternatives and declining prices while Google built their business on free services that are immune to price competition.
I can't predict the future, and maybe Vonage will bounce back. But those who compared Vonage to Google because both courted the individual investor missed these big differences.
Vonage should never have been marketed to the unsophisticated investor.
Update 2:58 PM: Vonage ended its first day of trading down 12.6% from it's IPO price, "turning in the worst IPO debut in nearly two years" according to the Wall Street Journal (subscription required).
Update 5/26 7:07 AM: Vonage dropped another 12.5% in its second day of trading, now down 24% from the IPO price. Sickening. Why would anyone buy stock from this guy?

