Link: Serif vs. Sans Serif Legibility
Which Are More Legible: Serif or Sans Serif Typefaces? by Alex Poole is a review and summary of a whole pile of writing about this. I'll cut to the conclusion (don't worry, it's not a spoiler since Alex Poole puts it in the first paragraph of the introduction):
To date, no one has managed to provide a conclusive answer to this issue.
Alas, none of this helps me configure liferea to improve its legibility on a 17" CRT monitor. (I would be happy if I could just clone a Firefox setup, but this is stupidly difficult and/or impossible for no good reason.)
(From someone I chat with online, when I was asking around about this.)