Private/non-certified channels have now been removed from Roku devices. See this article for an update to this article.
Roku announced that the company will disable all non-certified (aka "private") channels on all Roku devices on February 23, 2022. The primary intent of private channels was to allow developers to test channels before publishing them in the Roku channel store. Private channels also provided a means for limiting access to small audiences. For those unfamiliar with private channels, there are only two differences between public channels and private channels: Private channels are not listed in the channel store and so must be installed with the use of a "vanity code" through the Roku website; and private channels are not reviewed by Roku for compliance with technical requirements.
The existence of private channels carried a sort of mystique with some within the Roku user community, and listings of private channel vanity codes (including our own) became very popular, especially in Roku's early days. Aside from use for testing, many of the private channels were simply creations by hobbyists who didn't care about widespread dissemination, or they carried special-interest content that appealed to a vary narrow range of viewers. As Roku made it easier to publish in the public channel store and third-party tools such as Instant TV Channel simplified channel development for non-programmers, the number of new channels publicized in private channel lists has greatly dwindled.
Also hastening the demise of private channels was Roku's change in terminology - "private" channels became "non-certified" channels - which included a dire warning when installing a non-certified channel that "...if Roku determines that this channel violates copyright, contains illegal content, or otherwise violates Roku's terms and conditions, then ROKU MAY REMOVE THIS CHANNEL WITHOUT PRIOR NOTICE, AND YOUR ACCOUNT MAY BE BLOCKED FROM ADDING ANY OTHER NON-CERTIFIED CHANNELS."
As that warning suggests, a good number of Roku private channels are used for publishing content that doesn't meet Roku's terms of service for the public channel store. Adult channels have flourished since the first erotic streaming service appeared on a Roku private channel in December 2009. However, recent controversies over content on PornHub, including a lawsuit by three dozen women, spurred a backlash against Roku by some activists. In March, a letter signed by survivors of sexual exploitation and activists was sent to CEO Anthony Wood demanding that Roku shut down the Pornhub channel.
As a side note, many media outlets have been reporting that Roku is banning porn channels, but that is only a side effect of the overall private channel shutdown. Calling these headlines "clickbait", The Washington Times reports that a Roku spokesperson sent them "a statement saying that the decision to eliminate 'non-certified' channels aligns the company's screening of content with what Apple, Amazon, Samsung and Xbox already do with apps... The company said the fact that Pornhub and other adult entertainment platforms had found their way onto Roku televisions through private or non-certified channels was incidental to the decision, which intends to standardize the tools that app developers use to create channels."
Piracy is likely a bigger concern for Roku than adult content. In 2017, a court order banned Roku devices from being sold in Mexico after Cablevisión claimed that "hackers would develop unsupported channels with access to pirated content on Roku and sell subscriptions to users over WhatsApp." Although complaints in the U.S. never reached that level, many Roku users will remember the shutdown of XTV, a popular private channel with live streams of cable networks and on-demand episodes of popular TV series, after claims of copyright infringement.
Officially, neither adult content nor piracy are mentioned by Roku as reasons for the removal of all private channels. Instead, Roku's announcement states that it "is sunsetting non-certified channels to better align with industry standards on their two different use cases: developer QA testing of channels to be certified and published to the Roku Channel Store, and limiting distribution of channels to a small set of users." Private/non-certified channels will be replaced by two new developer features: Beta channels and the Independent Developer Kit (IDK).
The beta channel feature will limit a single developer account to 10 beta channels that can be installed by a maximum of 20 test users at a time. Beta channels automatically expire 120 days after creation, meaning they are no longer available on the Developer Dashboard and are disabled for all users who have installed them. The IDK lets individual developers and enthusiasts build and sideload applications on IDK-supported Roku devices for their own personal use.