The changes definitely change personal information flow but they don't affect privacy. It may affect "perceived" privacy but anything a student puts up on Facebook has to be seen as no longer private.
I've been thinking about this a lot myself, (as a Facebook user who is creeped out by the feeds! :-)) Does privacy intersect with the ways that information is aggregated? Does it affect privacy if disparate pieces of information that were once difficult to find, assemble and understand are suddenly aggregated with descriptive icons and temporal information? I'd argue that this DOES affect privacy. Aside from that, the changes are retroactive, so activities that were performed under old expectations of use are now displayed in this new, aggregated form. This seems like a pretty egregious error when it comes to designing around users' expectations of privacy... Andrea