What does the author's complaint have to do with the version Ubuntu is distributing? Are the 32-bit limitations present in Ubuntu's version not present in the most recent version? If they are, than who cares which of them he installed?
they can't be more explicit about it than pointing it out on the download page and giving a message upon the database startup
Uhh, yeah they can. On Debian-derived systems like Ubuntu you can make your .deb packages throw up dialogs that the user has to read and agree to before installation via debconf (http://www.fifi.org/cgi-bin/man2html/usr/share/man/man8/debc...). There's probably a way to do the same thing in RPM-based systems as well. If the warning is something that every user of the software needs to see, putting up a warning dialog and requiring the user to confirm having seen it before installation starts would probably be appropriate.
They could also write an error to the database's error log whenever data is discarded due to the 32-bit limitation. Someone mentioned above that it puts a message at the start of the log, but if that's the case IMO it's insufficient; most of the time people interact with logs by looking in them for a particular moment in time, not by reading them from the first line on. Logging the error on or near the moment the data loss happens would make the issue visible to people using logs in this manner.
Right, but the only person with the ability to do that is the Ubuntu maintainer of the package. Mongodb has no control over what they do and should not be held responsible for their actions.
Nope. In fact fedora developed packagekit said the idea was broken and caused a controversy over supporting it for ages