Value refers to the quality of a work; whether it is judged "good" or not. It also refers directly to monetary value and getting paid. In geek feminism this might translate to women being paid less than men for tech jobs, fiction, and other works.
A woman's work in an unpaid programming internship can also be devalued as being that of a "fake" internship, despite the fact that unpaid experience-gaining in Open Source participation is highly regarded in the industry.
This relates strongly to judgements of importance.