In other words, let's redo PageRank, but instead of which pages link to my page, use who follows/reads/spreads/reworks my stuff. A good idea, but probably tough

In other words, let's redo PageRank, but instead of which pages link to my page, use who follows/reads/spreads/reworks my stuff. A good idea, but probably tough to implement without some kind of standard identity system. (What does "who" mean on the web?)