No. No, it doesn't make sense. I don't care what my friends read - I only care what they think was good out of that. You can't just open up everybody's browser logs and call that viral.
I'm sorry, I simply don't see how you expect to be able to share selectively without UI. And unless that sharing UI is embedded in every possible page, you're kind of stuck with a popup. Unless it were a browser feature, I guess. Which doesn't make it not pop up, but makes the popup a little more trustworthy.
Think I get your point. For example, I used to have an app on facebook that shared the songs I loved on Last.fm. Those where very few, maybe 5* a year, so it made sense to auto-share them on facebook.
Edit: *Looked it up and it's more like 30 each year, ops.
Ah! Now I think I see, then - if I have a curated collection somewhere else and want it to share onto Facebook, sure - that makes sense. But you have to curate somewhere; just because some guy I went to high school read an article or listened to a song doesn't mean I want to hear about it.
I believe OoTheNigerian's point is that he likes it when the sharing functionality is rolled up into another thing that you do. Say, every time you rate a song 5 stars, or mark one as your favorite. He'd rather not get a popup asking if he also wants to share it on facebook (but have a config option which says "share my liked songs")