OMDoc is a markup format and data model for Open Mathematical Documents.
The current stable version is OMDoc1.2 (see the OMDoc1.2 Book and the OMDoc1.2 Repository. Current development work mainly focuses on OMDoc applications, but the experiences gained there flows back into the OMDoc Specifications. We are currently working on two fronts:
OMDoc.org serves as a community portal for the OMDoc community and as a clearinghouse for information about OMDoc-based projects and extensions to other sciences. OMDoc bibliography, OMDoc Tools and Projects