UPDATE: About three hours after this story published, Comcast told us that the $70 gigabit Internet offer is available in Chicago, contrary to what the company told us this morning. While Comcast didn't promote the $70 price, a spokesperson now tells us customers can get the lower rate on Comcast's website. The deal is $70 for gigabit download speeds and unlimited data, and requires a three-year contract. We've changed the headline, which originally read, "Comcast's $70 gigabit offer is only good in cities with Google Fiber." Obviously, this changes things dramatically, but this is the story as we wrote it before receiving the new information:

When Comcast launched its gigabit cable service in Atlanta and Nashville earlier this year, the company offered a $70 monthly price for customers who sign three-year contracts, half off the no-contract "every-day" price.

But when Comcast announced gigabit Internet for parts of Chicago this week, the no-contract price of $139.95 was the only one mentioned. The difference, as DSLReports wrote today, is that there's no Google Fiber providing competition in Chicago yet. While Google Fiber has tentative plans to expand to Chicago, its $70 gigabit Internet service is already available in parts of Atlanta and Nashville.

Comcast's Chicago announcement said the company "will test promotional pricing during the trial period," but didn't name any specific offers that are better than the $140 no-contract price. When contacted by Ars, a Comcast spokesperson said there is "nothing to announce at this time." The Chicago service may also come with a 1TB monthly data cap, as Comcast has previously only provided unlimited data to gigabit customers who sign a three-year contract. Otherwise, unlimited data costs $50 a month extra.

AT&T has taken a similar approach to its gigabit Internet pricing, matching Google's $70 price in cities where both companies operate and charging an additional $40 elsewhere. (UPDATE: It turns out AT&T has changed the price to $90, or $20 more than Google Fiber.) AT&T's lowest price requires opting into a system that tracks your Internet browsing history in order to deliver personalized ads.

Unlike Google Fiber and AT&T's GigaPower fiber service, Comcast's gigabit cable doesn't offer symmetrical speeds. New DOCSIS 3.1 (Data over Cable Service Interface Specification) technology dramatically increases download speeds, but the Comcast offering is just 35Mbps upstream. Comcast does have a symmetrical 2Gbps residential Internet service that uses fiber, but it costs $300 a month, with installation and activation fees of up to $1,000.

Google Fiber, meanwhile, has been re-evaluating its expansion plans as it considers whether to use high-speed wireless technology instead of fiber.