It's surprised me somewhat how some maintainers don't seem to interact with the upstream author(s) of the software that they package. To me, it seems the natural way to operate. It's a partnership between the author who has the intimate knowledge of the code and the software, and the package maintainer, who knows how to package for the distribution.
I'm not meaning to point fingers at peoply by using these examples, they're just some cases I've come across recently, which has prompted me to write about it.
When Andreas Barth recently made a request for adoption of iproute, I glanced over the current bug listing, and in my opinion, saw a lot of bugs that weren't specific to the packaging of the software, and should have been forwarded upstream. When I asked Andreas what sort of a relationship he had with upstream, I think he said something to the effect that he hadn't had any dealings with them during his maintainership of the package.
Similarly, the other day I was looking over the list of orphaned packages with the maintainer not set to the QA group, with the intention of perhaps doing an upload or three in some spare time that I had, and I stopped upon html2ps, which had a good number of bugs open.
I dropped the upstream author an email, as again, a lot of the bugs looking like fundamental issues with the software, not with how they were packaged in Debian. The author replied, saying he hadn't known of the BTS page for his software, and hadn't known of some of the bugs. He actually went so far as to write a bit of a narrative to a lot of the bugs listed, which I will have to followup the various bug reports with.
I realise that there is personal style to package maintainership, and that some maintainers may be intimately familiar with the source code, but at the end of the day, we all want "Zarro Boogs" in our packages, so I'd think its in our best interests to do whatever we can to help make that goal come about as easily as possible.
I'm also personally of the opinion that the Debian packaged version of some software should attempt to walk and talk as similiarly as the original upstream version. In an ideal world, all distros would strive for this, so there'd be a degree of interoperability between distributions for given software packages. So to this end, I'd rather see an upstream bug fixed upstream, than fixed in a Debian package specific manner, which caused the Debian package to diverge in behavior from upstream.
For the packages I maintain, I'm on fairly familiar terms with the upstream authors. For packages I ITP or adopt, I generally ping the upstream author when I file the WNPP bug. If I don't get a response from the upstream author, I think twice about going through with the adoption or initial packaging. Like I said, it's a partnership, so it's a bit harder when you're on your own, and you're not intimately familiar with the code.
So, get to know your upstream. From my experience, it's a win-win situation.