My take on multitasking is that it mostly doesn't work, at least not for cognitive activities. But, I guess it depends on your definition of "multitasking" and "working/not working".

There are, perhaps, some activities which most people can multitask at - such as, driving a routine route while carrying on a light conversation. (But even that might distract from one or the other) But try something more complex - such as even trying to carry on a simple conversation while driving in an unfamiliar area or when you're lost - and quickly you'll find you can only focus on one thing at a time.

So, my sweeping generalization of people surfing and talking simultaneously is that if the two activities are very unrelated, (different topics) it's likely far less attention is being paid to each than the level of attention you're giving to reading your single article.