Weak signal analysis
Use of common economic patterns to identify where and when to attack.
Monitoring clues to determine internal activity by a competitor.
It is very helpful (perhaps mandatory) to have an approximate map of the competitors business, so that changes to lower-level components have meaning.
It's like watching washing lines of foreign sailors to determine when a submarine fleet is about to set sail (a very old trick)
Watching job listings to see what type of key employees are being hired, or which departments seem to be rapidly growing
Watching for significant commitments or investments in a supply chain. E.g. Apple making investments in flash memory manufacturers signaled that they expected to consume large quantities of this component. An analyst could look at Apple's current or likely business to see which areas were likely to to need this component, and were therefore probably growing.
AWS can withhold information about their costs, but since they may lease space in buildings, you may be able to find out about the power budget in that building and estimate the number of servers that can support. From that, you may be able to estimate AWS' actual physical capacity and thus part of their costs.
X : How do you mask signals? Me : Reassign registration (change tail numbers) every week. Randomise travel (i.e. more public transport in the rota) and expand use of private jet to other staff. Use video conferencing. Hold meetings in a sea of meetings, at big conferences etc ... ... you can't stop a dedicated watcher, i.e. someone like me will always find a way through the masks but you can prevent casual analysis. The goal is to make the other person / company easier to track than you.