What to expect from the community
For most projects, including commercial open-source projects, localization and some bug reporting constitute the primary contributions from the community. The key for these projects is to ensure their architecture then allows for customers and other self
I stumbled across this news from Openbravo this morning, and thought it indicative of the type of contribution typical to commercial open-source projects. Egyptian accounting for Openbravo's open-source ERP platform. No way that a proprietary software company is going to write that, not until every other aspect of the product is already complete.
For organic open-source communities, bug fixes, code contributions, etc. can be expected, though not to the levels commonly expected. It turns out that all (or nearly all) communities are small, even for projects like Linux and Apache. Some, like Drupal, break this mold, but they are the exception, not the rule.
For most projects, including commercial open-source projects, localization and some bug reporting constitute the primary contributions from the community.
The key for these projects is to ensure their architecture then allows for customers and other self-interested users of the software can easily contribute pieces without having to grok the whole. I call it "drive-by development." (This is, incidentally, where I think Drupal excels, as does Linux, Mozilla's Firefox, and others.)
Open source is excellent at creating things like Egyptian accounting rules packs for Openbravo. Just don't expect your community to do all the heavy lifting of development for you. They won't. They have jobs, remember? :-)
(On the topic of jobs, it is, of course, true that some people are fortunate to get paid to write open-source software, but probably not for your company. This changes a little if they're a systems integrator with a practice built around your software, but even then most SIs keep those enhancements for the good of their customers, and generally don't contribute them back for the good of the overall community. There are plenty of good reasons for this, but that's another post....)