Update "How to subscribe to YouTube Channels" page
Knowledgebase article is outdated:
Youtube changed the URLs for Channel/User RSS feeds. See this thread on Reddit:
Google - Use RSS with YouTube
Get RSS updates for a single channel
To get an RSS feed of a single channel’s uploads, paste the channel URL into your RSS reader.
Get RSS updates for all subscriptions
To import all your YouTube subscriptions to your RSS reader, you can use our OPML file download feature:
Download the OPML file by clicking Export subscriptions at the bottom of your Manage Subscriptions page.
This will download a file named "subscription_manager.xml".
The two links to add feed are
Using VICE NEWS as example, the differences of the two are: the channel_id one update an hour or two earlier, shows how popular each feed is and more users.
How to subscribe to YouTube Channels
If the channel does not have a custom url, the code after /channel/ is the channel ID
If the channel does have a custom url, you can still get the channel ID by click the channel name when watching one of the videos, the link would be https://www.youtube.com/channel/UCZaT_X_mc0BI-djXOlfhqWQ instead of https://www.youtube.com/user/vicenews