As some of you might know, I am a big VoIP head, and I use it exclusively (now through Google Voice) to call my family in Greece. Interestingly enough, a few months ago, right after I got invited on Google Voice, I sent a pretty "get off your butt" feedback message to Google Voice, suggesting that they should either buy Gizmo5, or at least create their own VoIP SIP service -- since I am not always interested in using Google Voice via my landline or cellphone, in order to cut down costs.
So when I read the news today that Google bought Gizmo5, I rejoiced. This is what it's needed to bring tele-communications to the 21st Century: the free/cheap prices of Google Voice, by way of an internet connection.
Of course, there have been many VoIP providers so far, but none offers completely free US calling, with so cheap international calling (which has the potential to also become completely free in the future when-and-if Google spreads their Google Voice project to other countries too).
The only stinky point for me with Gizmo5 has been that there was some lag in the audio every time I used it (my mom keeps complaining about it). Lag that doesn't exist with the Skype service. I keep hoping that Google will fix whatever technical difficulties Gizmo5 has had.
Another interesting point is that if there's a new version of the "Google Voice" application for iPhone and Android that incorporates a VoIP SIP stack, then Apple will have NO legitimate reason to reject the app again, because with a VoIP stack incorporated, the app won't be different than Skype or other SIP apps found on the AppStore.
In conclusion, this is a great day for consumers, especially those who have family abroad. This is a huge blow for cell carriers, of course, but what can you do? Technology evolves, and just like in the music business, the companies must adjust to new realities. And Google just adjusted to them. AT&T, it's your turn.