apt-get update is annoyingly slow for modem-based users, and also puts an unnecessarily heavy load on the servers, for the common case where only a small change is made to the Packages or Source file for a part of the distribution. I just sucked down a megabyte-sized file to find that one line had changed, for a package I don't care about. Why can't apt-get update send diffs to these large files rather than sending whole files?
One possibility would be to just build the thing on top of anonymous CVS. CVS already knows how to just send the changes to a file.
