> 99% of raw data is useless. Just as a rule.
Well, as a non-facebook user, I think 99.9999% of facebook data is useless :) But facebook is in the habit of tracking everyone's surfing habits across the web (through "like" links), and I assume they do more than just "increment a counter with it", even if they don't keep every single detail.
Most of it likely gets tossed into a program to determine if somebody actually needs to do anything, or if something is actually breaking.
For example raw user interaction doesn't really grow. While the event is likely ~1kb or so of raw data, at the end your just incrementing a 64bit counter.
This is a baseless exaggerated post but should shed some light on.