not always, often stuff is stored in the db that we want to work on in dev then deploy to production.
but it would be nice to be able to export a selection of nodes to code and preserve there id's, content and metadata. maybe you'll find a features contrib mod http://drupal.org/taxonomy/term/11478 but i've never heard of one.
If you want to create content on your dev or staging site and push it to production, check out the deploy module: http://drupal.org/project/deploy
Tracking changes to nodes in production is probably best left to Drupal's built in node versioning system. Diff (http://drupal.org/project/diff) is a handy module to track changes between revisions and if you want a little more advanced workflow check out revisioning (http://drupal.org/project/revisioning) and workflow (http://drupal.org/project/workflow). Good luck!
If it is a small amount of content, such as a handful of pages for a brochure site, putting them in a feature might be best.
If it is a site where customers or visitors generate content on the site, then periodically re-initialize your dev and staging environments with copies of the live DB, running it through a script to anonymize all the user info and change passwords and etc.
If you want to create content on your dev and move it live, then doing a full database copy and moving it live, with settings that are particular to live overridden in settings.php, is probably the best way. I advise against this, basically you are re-launching the site for every change.
If you are truely desiring to be able to create content in multiple different places and move it to live, then probably the best thing to do explicitly program and configure for that, by specifying feeds of the content and setting up the different sites to ingest each other's feeds.
