This document discusses various options for sharing museum collections online and how to determine which options provide the best return on investment. It outlines different levels of open access from sharing content and metadata to full aggregation and outlines platforms like Google Cultural Institute, Wikimedia Commons, commercial picture libraries, and Europeana. For each option, it discusses the effort required and potential upsides like increased exposure and audience as well as downsides like losing control over content or data. Key recommendations include defining your approach based on your audience and values, using high quality images and metadata to unlock multiple options, and using commercial activity to generate income to reinvest in further opening collections.