- minimise the amount of time T80 that it takes 80% of the target audience to learn the news
- maximise the eventual penetration of the news into the population P∞(informed)
- minimise the maximum or mean number of redundant notifications that are received. Rmax, Rmean
∗ that is: all people wish to hear it once, and all people are willing to redistribute it.
† like LiveJournal, or more generically the Blogging Network.