So what's it going to be with VoIP provider Vonage? The next Google or eBay (which already swallowed up Vonage competitor Skype)? Or the next TiVo (which everybody adores but can't make a dime)?We'll know soon enough after yesterday's news from Vonage that the company will be trying to raise $250 million in a much-anticipated IPO. The offering may not be the slam-dunk many thought it would be when Vonage first emerged from anonymity to begin a run that has it now controlling more than half of the consumer VoIP market in North America. As this BusinessWeek story nicely summarizes, Vonage faces a host of obstacles that include increasing competition -- especially from deep-pocketed major players -- rising customer-acquisition costs and declining revenue on a per-line basis.In fact, doubts about the company's long-term prospects have been bubbling up for about as long as the IPO rumors.\u00a0\u00a0 One thing this IPO will not be is a referendum on VoIP; that genie's not going back into the bottle.The only question is who's going to find a way to make money off it -- and who's going to go broke trying.