Actually not using Ubuntu any longer since I've switched to Linux Mint very recently.
However, I still feel this is a great site for exchanging general ideas on Ubuntu and Ubuntu-like distributions.
Q&A for professional and enthusiast programmers
Q&A for Ubuntu users and developers
Stack Exchange Network staging zone, where users come together to build new Q&A sites
Q&A for computer enthusiasts and power users
Q&A for professional system and network administrators
Q&A for apps, scripts, and development with the Stack Exchange API
Q&A for database professionals who wish to improve their database skills and learn from others in the community