Abstract
Microarray expression profiling is instrumental to our understanding of the function of the genome. Resolution of functionally relevant expression patterns will require the analysis of large data sets compiled from multiple investigators. For this and other reasons, I argue that it is crucial for array data to be publicly shared in a format as close to the 'raw data' as possible. Issues such as protection of intellectual property, ensuring quality of the data, and the format and timing for sharing array data are also discussed.