I would hazard the guess that twitter's "show tweets to other people" is 1/40th of the functionality piled into twitter; some other large functions would be thi

I would hazard the guess that twitter's "show tweets to other people" is 1/40th of the functionality piled into twitter; some other large functions would be things like "track ad sales" or "improve engagement" or "allow random law enforcement organizations to engage in whatever access is needed for any particular part of the world" Each of those is going to be a huge pile of code and all of it working together is going to N! your complexity.