I link to Nick's blog because it has plain simple explanations that cover the concept of blocking vs non-blocking.
If they can work it out from BWD then Nick's blog is a more complete and sensible explanation.
If you've never seen it, go have a look at how it's done.
It's also a good meter of the student because if you can't pick that up then you either need to cover basics or your attitude/attention span or maybe you're just some other way not cut out to write code past the Weekly Reader level.
If I link someone there and it's clear they didn't bother while still pestering for code then why bother waste my time on that person? I spend as long or longer on a lot of posts than it takes to go through that. I'd rather my time went to someone that won't waste it.