I don't know how feasible that would be to have USN threads feed into a twitter account. I think it would be relevant and i would like to see it someday. What do you think?
You could always subscribe to the USN, and get a notification for every topic.
And if you don't mind getting spammed with messages, make it send an e-mail to you every time.
Really, there's no need for a twitter account.
Yeah I'd follow this for important news, not all the minor stuff and "hey look guys did you know the XL is bigger than the original here's a pic" crap posted in USN.