This document discusses reasons for putting GIS applications on the web, including that the web is ubiquitous and spatial data is important to share. However, past attempts have overcomplicated web GIS by directly porting desktop functionality and dragging along unnecessary "GIS baggage." The document also references the "Holy Trinity" of desktop GIS - map, table of contents, and toolbar - being dead for web applications. It concludes by suggesting rules for web mapping include keeping it simple, focusing on real users, making beautiful maps, offering less functionality, and prioritizing workflow.