the midden

Let’s say a person has 100 contacts that are weak tie friends, and 10 that are strong tie friends. Suppose the chance that you’ll share something is very high for strong tie friends, say 50%, but the weak tie friends tend to share less interesting stuff, so the likelihood of sharing is only 15%. Therefore the amount of information spread due to strong and weak ties would be 100*0.15 = 15, and 10*0.50 = 5 respectively, so in total, people would end up sharing more from their weak tie friends.

Rethinking Information Diversity in Networks | Facebook