Is MathOverflow a subsidiary of Stack Exchange? Did MathOverflow lose its independence when it migrated to the Stack Exchange network?
While the MathOverflow site is operated by Stack Exchange, Inc., the domain and the MathOverflow name are owned by the MathOverflow corporation. The MathOverflow corporation is completely independent from Stack Exchange and its mission is to ensure the continued operation of the site in a manner that meets the needs and expectations of the community.
On May 17, 2013, MathOverflow became a nonprofit nonstock corporation in the state of Delaware. On June 24, 2013, MathOverflow signed an agreement with Stack Exchange, Inc., to migrate the original site to the newer Stack Exchange 2.0 platform and join the Stack Exchange network. On March 26, 2014, MathOverflow filed an application for 501(c)(3) nonprofit status, which will allow the corporation to receive donations to ensure its continued operations. This process was made possible through a generous grant from The Alfred P. Sloan Foundation.
The agreement with Stack Exchange has several clauses that to ensure that MathOverflow can continue to meet the needs and expectations of the community. The most important of these is the "jump ship" clause:
Subject to Section 8, should MathOverflow wish to migrate its data outside of the Stack Exchange network, Stack Exchange shall, within thirty (30) days of receipt of a written request from MathOverflow, provide MathOverflow with a complete and current database that contains all the data necessary to recreate MathOverflow on MathOverflow's own servers and software. Following such transfer, Stack Exchange will cease all use of the MathOverflow database.
Another important clause ensures our ability to make small modifications to the site:
The complete agreement can be found here.