One little thing: In my opinion the labels 'Google', 'Wikipedia', 'Twitter', etc. don't need to be fixed on mobile since you already have to icons above it and it does take up a bit of vertical space.
Other than that a nice concept.
That is a really good UX optimization find. Yes on mobile, since it is just 1 column at a time, I could remove the title label.
The label does help to anchor the column a bit more clearly and gives consistency between mobile-desktop. What do you think about that? Is the extra few pixels height more valuable? Really value your opinion!
I'll try coding it up tomorrow morning and see how it feels!
I only had time before to test it on mobile on my commute. Having seen the desktop version now I understand your concern. Maybe there is a way to just reduce the size of the information a bit but still keeping it structurally as is? I also think that most people can identify the source of the information just based on how it is structured (longer texts for wikipedia, youtube/twitter/reddit with its own branding, etc.) but we would need more opinions on that.