Remodel stats around "reachability" concept

[free-ghz]

• Of all links globally, how many of them can reach here?
  • What's the chance of that (since it's a stochastic process?)
  • Maybe, per page, you typically click one link. So what percentage of all clicks on any page would reach here, on average?
• Then, in stats, sort tags by their probability to increase the reach of some page.
  • Or by the reachability of the least reachable page they link to?