Drupal.org and groups.drupal.org provide several ways for community members to interact with other community members. Specific members can be reach by their contact form. Forum posts allow you to reach out to those who are watching (both as volunteers and as paid consultants if you are willing to pay). You can make direct contact with those tracking or monitoring specific modules by posting an issue to the module queue. Let's not forget the IRC (http://drupal.org/irc).