Canonical/Ubuntu provides many services for developers/users, but there doesn't seem to be a complete list of these services anywhere. These services help get people involved and help developers work on issues.
There is a few couple of Ubuntu services (or subdomains). Not all of them is strictly developer-related:
Ubuntu Pastebin - http://pastebin.ubuntu.com/
Official Ubuntu Pastebin
Ubuntu Wiki - https://wiki.ubuntu.com/
This may be obvious...
Ubuntu Official Documentation - http://help.ubuntu.com/
This may be more obvious...
Ubuntu Brainstorm - http://brainstorm.ubuntu.com/
Submit your Idea for Ubuntu here
Ubuntu Forums - http://forums.ubuntu.com/
This leads to the Official Ubuntu Forums.
Planet Ubuntu - http://planet.ubuntu.com/
A blog for Ubuntu developers written by Ubuntu developers.
Ubuntu App Developers - http://developer.ubuntu.com/
A site for Developers that develop apps for Ubuntu.
Ubuntu Mailing List - https://lists.ubuntu.com/
You can subscribe stuff about Ubuntu here.
Ubuntu Fridge - http://fridge.ubuntu.com/
An Information Hub for the Ubuntu Community.
Ubuntu Error Reports - https://errors.ubuntu.com/
Error reports about Ubuntu goes here.
Ubuntu Harvest - http://harvest.ubuntu.com/
Harvest makes it easy to find low-hanging opportunities in Ubuntu. It aggregates the mass of todo lists we use every day so it's simple to find and coordinate work.
Ubuntu Single Sign On - http://login.ubuntu.com/
Manage your Ubuntu SSO account here.
Ubuntu Status - http://status.ubuntu.com/
This page shows the progress towards completing all of the Topics for the current cycle.
Ubuntu Apps Directory - https://apps.ubuntu.com
All apps in the Ubuntu Software Center
Ubuntu Developer Summit - http://uds.ubuntu.com/
UDS Official Website
Ubuntu CD Images - http://cdimage.ubuntu.com
All Ubuntu ISO's - From Warty to Quantal
Ubuntu Packages - http://packages.ubuntu.com
Information about Ubuntu's Packages.