Seconded, I don't like Serif fonts for non-book reading.
However, the historical reason why sans-serif are generally recommended over a serif on a computer screen was a matter of practicality. The computer monitor simply couldn't replicate the tiny detail required by serifs. Higher resolution screens are becoming more common place, which is why you'll see more serifs in use online (IMO... correlation vs causation and all that). Somewhere along the line someone cited scientific articles to help justify this practice, but I'm convinced it became common place was really for practical reasons/aesthetics more than anything.
[1] I haven't personally done a literature review, but this post is great in discussing the conclusiveness around the research (and readability vs legibility vs....) http://alexpoole.info/blog/which-are-more-legible-serif-or-s...
Here's an interesting anecdote I just remembered, though. A psychology professor of mine was attempting to replicate another researchers work. The result couldn't be replicated when the stimuli was displayed in sans-serif fonts, but it was replicated when they finally used the font the initial researchers did: a serif.
I'd bet serifs/sans may have some sort or psychological implications but I doubt it's as straightforward a relationship as often presented