Google Voice (formerly GrandCentral) is starting to open up to people who had requested invites to the service. Whether you want to describe this as a next-gen telco service or "unified communications," it's potentially very powerful and appealing given the fact that its free and feature loaded, with the promise of more features to come.

As powerful as it is ordinary users will need to be educated about how/why to use it. Then there's the issue of "yet another phone number" to socialize among your friends and colleagues. But assuming you do that -- and Google remains committed to the service over time -- it represents the prospect of a "single number for life." However one of the things that is high on the potential feature list is the ability to port your number to Google voice. 

Despite the enthusiasm from Silicon Valley types for the service ordinary users are totally ignorant of Google Voice and are unlikely to adopt simply because it becomes generally available. This is a potentially huge product (over time) for Google with lots of revenue implications. It could be even more strategic than GMail has become for the company. However Google will need to make the case for the service. 

Previously, payments platform Google Checkout was launched as a product with potential appeal to both consumers and Google advertisers/e-commerce sellers. It was touted as an "PayPal killer" hyperbollically. I argued at the time in 2006 that Google needed to actively sell (market) Checkout to consumers to make the system work. Google did some limited online advertising for Checkout, aimed manily at AdWords advertisers and e-commerce sellers. But the failure to mount a broader consumer campaign for the product caused it to largely fail.

Checkout gets another opportunity as the payments back end for Android's paid apps marketplace. It could become a broader mobile payments platform as well.

Over the years Google has warmed up to consumer marketing, offering some outdoor awareness ads for Goog-411, Google Transit and some limited sponsorships on public radio and TV. (It's doing court-mandated newspaper advertising in connection with notifying authors of its Book Search settlement.) Most recently it more dramatically started doing TV ads for its browser Chrome. It needs to do something similar for Voice if it hopes to build awareness for the product.

If number portability comes that will remove a big barrier to adoption but Google still needs to fundamentally answer the question "why" to mainstream users. Exposing the features, benefits and price (free) through a mainstream media awareness campaign will eventually be critical if Google hopes to make Voice the success it has the potential to become.