There are different views on the attention span thing. A quick google search turned up The Gaurdian: mixed results on attention span from March 2013 and The Gaurdian again, Definitely reduced attention span from March 2012 I googled "does the internet affect attention span" A link to the results On the other question, if I'm sitting, enjoying a good book, I will either respond quickly, ignore the text, or just not hear my phone go off, and I'm generally none the worse.
Haha, I could have done some googling I guess, but I didn't, because what I actually meant was "I think these sorts of articles are generalizing, assumption-making crocks of shit." Fact is, we don't know yet whether the internet is messing with our attention spans. And what if we're misunderstanding the causes? I was trying to watch the BCS football thing on tv but it bored me and the article on my laptop was extremely interesting -- so now I'm sitting on my laptop reading instead of watching football. Did the internet evilly steal my attention? I give my attention to the most interesting thing in my vicinity and always will, no matter where it comes from. That's just human.
Long-form reading might just be the last thing the Internet helped us filter. People would sit through a long, dull book in the 1950s because there wasn't much else to do. Why suffer through that when someone's written this 15,000 word account of their life in a dictatorship?