Ok, I gave up on the idea of staying offline in the mornings.
Reason: Because of my Market Watch column for Writersmarket.com, I need to surf the Web for publishing industry info each morning. I tried to make notes of stuff that would be good tweet and blog post material later in the day, but found that the info always seemed stale later on, plus distracted me from whatever else I was working on.
For me, it makes sense to do the info sharing while I'm online doing the research; I'm just being more careful about how long I spend doing this. Right now, I'm keeping a detailed time log about how I spend my time each day. I don't plan to do this indefinitely, but it's certainly helping me see where and how I spend my time.
My new plan: To stay completely offline from noon until 3 pm. Thanks to those of you who suggested Freedom, a Mac productivity app that cuts you off from the Internet for scheduled amount of time. The only way to re-enable Internet access is to force-quit the app or reboot. How are the rest of you doing with your productivity goals?