Signs are pointing towards widespread ability to make Voice over IP (VoIP) over Wi-Fi calls: But will revenue follow? Many of the uses of voice over Wi-Fi reduce costs or shift usage; one firm puts revenue in 2009 for long-distance Wi-Fi voice calling at just $20 million, according to the article.
But cell phones with Wi-Fi and Wi-Fi phones aimed at the home market could drive more rapid adoption. Imagine a single phone that you carried everywhere, but with higher quality and lower cost than a cell phone whether in your house or deep in a convention center.
The main problem with a roaming Wi-Fi phone is authentication on networks that require accepting terms at a gateway page, logging in, or paying for use. These are not insurmountable problems.