Tl;dr
Things that are too long for what they're trying to say are what get that treatment. Meanwhile I've often prefered long chunks of text online, as long as they're interesting. But the easy availability of distractions when on the computer does make it harder to sustain focus on a single text: easier to read a book than an e-book.
One a side note, the existence of long usenet or comment threads is no argument for the idea that long texts are possible online, as there's enough novelty in these threads (usually) to sustain one's need for novelty.
I have no problem with outsize texts online. What I will never look at is video (unless it is otters holding hands or nom-nom kitty). I have many times clicked on a story I thought was going to be text to find that it's video -- click! -- close tab. "Blogging Heads"? Never ever.