Yeah I understood that. But unless your friends are constantly checking for new links shared on Delicious, you would have to notify them that you've posted a new link. SMS, phone call, AIM, email, somehow.
You could subscribe via RSS. I had a bunch of delicious feeds that basically just fed me new sh*t on exactly the topic I was interested in. Because they had been tagged by humans I trusted. It was great ;-)
People actually checked Delicious like they checked Twitter or Facebook.