"Then you collect the data you need (and just the data you need) to answer those questions." If you are providing something to anonymize activity- then sure, i

"Then you collect the data you need (and just the data you need) to answer those questions." If you are providing something to anonymize activity- then sure, if it is legal. And you want to store as little data as possible that would be hazardous if it was made public. But for everything else, it's probably not a good idea to have this attitude. There are many questions you don't need to answer before you need them, and then it would be good or even necessary to have them historically. For example, auditing changes made to the system or data, logging some requests and responses, tracking user behavior for analysis by marketing, etc. Over time, depending on the site/service, you may want all those things and more.