Data activism has emerged as a response to asymmetries in how data and
the means of knowledge production are distributed. This article examines
MyData, a data activism initiative developing principles for a new
technical and commercial ecosystem in which individuals control the use
of personal data. Analyzing material collected at a formative event
shaping MyData activism, we examine how more just data arrangements are
framed to enhance equal participation. Our analysis shows agreement on
what is ultimately at stake: individual data agency and fair competition
in the data economy. However, two alternatives are offered for what
participation involves. Collaboration with commercial actors favors
framing participation as agency in data markets, thereby potentially
limiting the scope of what is at stake. The alternative framing presents
a rights-based understanding of economic and civic agency, potentially
leading to a broader understanding of participation in a datafied
society.