Eckerd College in Florida has instituted portfolio assessment in writing classes, a method which invites students to engage in learning on a variety of levels. Portfolios encourage students to consider the responses of various readers in their revision processes, claim ownership of their writing, review the papers they have written in college, decide which ones they think are best, and articulate their writing strengths. Students' annotations in their portfolios provide a rich illustration of student learning, offer examples of the intricate intersection between context and cognition, and demonstrate some of the meaningful rhetorical acts students construct in the process. Students' annotations demonstrate numerous cognitive tasks which are outside the province of standard assessment exams, such as a well-developed consideration of their readers and of the context in which their writing will be read, the development of a highly individualized philosophy of writing, and articulations of their learning. (Four questions for future research are attached.) (SR)