Radical transparency is a practice in which an individual or group makes as much about themselves public as possible. It might include, say, an individual publishing their home address and phone number prominently on their webpage, or a company providing public read access to their accounting software.
Distributed communities like open source software and Wikipedia approach radical transparency in some ways, particularly conducting many of their discussions and conflicts in public indexable form (eg publicly archived mailing lists). Depending on the community this varies from intentional to being simply a side-effect of needing to keep geographically distributed contributors informed of the project's status.
As a feminist strategy
On occasion, feminists use radical transparency to pre-empt or defuse potential criticisms or harassment. For example:
Being "out" about having a marginalised identity has long been an activist strategy and could be considered akin to radical transparency.
Dangers of radical transparency
Radical transparency can be dangerous to marginalised people, because it may provide additional information that abusers can use to target them. In addition, even routine practices of theirs might be unduly criticised when revealed by radical transparency (eg, their practice of earning a living).