Om Malik has a pretty good handle on Vonage as he's talked with Jeff Citron and comes from the investment banking world, so when Om comes to a conclusion, I tend to look at it and then add on.
In my mind Vonage is using the dot.com model of "get big fast." They are doing this through super aggressive marketing, including an upcoming year long campaign in the range of $50-75 million dollars with their two new agencies, and now saying they are going to hire another 600 people to work in supporting roles.
But it's not all flat roads and cotton for Vonage. The landscape is not theirs alone. While other players were out there just behind them--all who laid back on marketing because they didn't have the money--VoicePulse, Broadvoice or lacked the marketing bent, Packet 8, Lingo, etc. or now the consumer savvty and smart and well funded products from AT&T with CallVantage, Covad and just about all the RBOCs, plus the cable companies using either Level3 or Net2Phone are in the game.
Vonage had the lead, and that led to their growth. They marketed while others played the technology building or assembling game. But, that approach won't work any more.
The others are all realizing they need to market and they are. What Vonage lacked was the deal with the big cable company or companies. The reason they couldn't go there was they lack the QoS that would have kept the cable operator's customers happy. Sure they signed some small deals with some smaller MSO's but since Vonage doesn't break out numbers, we don't know how successful those relationships have been.
So, what I'm seeing is that Vonage is really not doing anything different with the money they raised. Marketing and people to support the customer. Until Vonage gets some infrastructure of their own they are really just a customer acquisition company.
Smart companies looking to partner with a VoIP player, or VC's and investors looking to make money on an investment would be wise to look in the direction of the companies who can deliver an end to end solution that doesn't know how to market. That's really the easy part. Getting the QoS right and doing all the things necessary to keep the calls sounding great, well that's the harder part.