Good point. Privacy gets much harder when seemingly harmless pieces of data can be combined over time.

Stackernerd

Surviving a transaction graph observer that is able to intersect many small pieces of information. This is a good reference: 

bitcoin

Coinjoins

Bitcoin CoinJoin Privacy Faces a New Surveillance Challenge‽

Surviving a transaction graph observer that is able to intersect many small pieces of information. This is a good reference: https://gist.github.com/nothingmuch/d84ba390d89b5b08897af2d95009c2a1