XLDB attempts to tackle challenges related to extreme scale data sets. Main activities include identifying trends, commonalities and roadblocks related to managing and analyzing extreme scale data sets, and facilitating development and growth of appropriate technologies including (but not limited to) databases.
Close to a thousand people worldwide participate, and the community is rapidly growing. The subset of the community gathers each year at the annual open XLDB event, typically organized at Stanford University in September or October. If you have experience with large data as a user, developer or a provider, get involved!