In the coming weeks, Comcast is rolling out a new feature that turns residential customers' new Xfinity Wi-Fi routers into public hotspots. The rollout starts in Houston on Tuesday, and the company says it'll be in millions of homes across the country by the end of the year. That's a big hotspot!It's easy to have mixed feelings about this idea. On the one hand, it's wildly convenient. What Comcast is essentially doing is creating the country's largest public Wi-Fi network by simply enabling people to share their connections. Of course, it's not entirely public. You have to be an Xfinity customer to be able to log on to the new super hotspot, but as long as you pay your bill, there's a decent chance you'll never have worry about Wi-Fi again.