Is it just 8,000-word epics that make people hit “Read Later”? Some interesting stats in this article about the type of pages that are being saved with Read It Later (which stands in here for any number of similar tools).
What you can see here is that, by far, the largest number of articles that are being saved are short — under 500 words. The number of articles saved drops off quickly at word counts higher than that.
[…] the evidence seems to be that people find time-shifting useful regardless of length, and that using these tools for really long work is more of an edge case than common usage. It appears the user’s thought process is closer to “Let me read this later” than “Let me read this later because it’s really long and worthy.”