Over 50% of the viewing on Comcast’s Flex streaming TV device is free, ad-supported, according to an update Comcast shared this morning. Comcast didn’t identify viewing shares by specific services, but said four services - Peacock, Xumo, Pluto and Tubi - were “routinely among the most viewed apps on the platform.”

Comcast offers the Flex box for no extra charge to its 31 million Xfinity broadband users and said it had over three million Flex boxes deployed as of March. Flex users also get free access to Peacock Premium, the $4.99 per month ad-supported tier that includes all Peacock content, including all seasons of “The Office” which is Peacock’s most valuable content and gets significant promotion in the app. Comcast also noted its “content forward design that puts free programming front and center.”

Given these dynamics, it’s likely that Peacock is the most-used app by Comcast’s broadband subscribers. Comcast said the live guide on Flex, which includes FAST linear channels is the “second most-viewed destination on Flex behind the home screen.”

Flex also offers access to all the biggest SVOD services including Netflix, Disney+, Hulu, HBO Max and Amazon Prime Video along with YouTube, by far the biggest ad-supported service. Comcast said streaming on Flex and X1 was up 73% in 2020 and that it accounted for 71% of all downstream traffic on its network in 2020, up 70% from 2019.

Though Flex is used primarily as a retention tactic for broadband subscribers currently, on last week’s Q1 earnings call CEO Brian Roberts signaled broader ambitions, saying “I really do think the next phase that we’re working on and developing for and turning our innovation focus is that this (Flex) is a long-term platform opportunity for us. And the aspect of the company that we have called Xumo, that’s one piece of being able to drive, help drive advertising. We could participate in revenue in the app splits that we get.”

That sounds familiar to the platform playbook Roku has run - gaining a large installed base of CTV devices, and then monetizing the audience through advertising (it’s also what Samsung, Vizio and LG are doing). Comcast already has significant adtech infrastructure anchored by its 2014 acquisition of FreeWheel, not to mention significant content assets and viewership in NBCUniversal.

With all of these different pieces, I think it’s fair to say Comcast is positioning itself to be a far bigger player in ad-supported streaming going forward, led by Flex and Peacock.