At last, Comcast's promised gigabit internet rollout is starting in earnest. The cable giant is beginning an "advanced consumer trial" of the extra-quick, DOCSIS 3.1-based broadband in multiple Atlanta neighborhoods, with additional cities coming this year. You'll have to make a big commitment if you want in, though. It costs $70 per month if you lock yourself into a 3-year contract, and it's an eye-watering $140 per month if you want the freedom to leave at any time. And it gets worse: if you don't commit to that contract, you'll have to accept a 300GB monthly data cap that's trivially low for the speed. Assuming you max out your connection, you could blow through your limit in 40 minutes.