The site macros (e/client & e/server) let the programmer declare what site an effect must run on. The network is not explicit, only implied. For example, platform calls like (query-database) or (.createTextNode js/document) or (check-password) are inherently sited. Siting is essential complexity (arguably the essence of a distributed system), and consequently we as programmers are hyper-aware of where (at which site) our effects must run, and we require perfect control over their placement.