Why do people do blogs? Why on Earth would anyone put something on public display as personal as an attempt to lose weight?
I think some people want a pat on the back from others and need approval as motivation to keep going. These are the people that go to weight watchers and stay for the meetings.
I think some need accountability. Their motivation comes from embarrasment if they don't stay on track. A few others do this as a "dear diary" kind of thing, oblivious to the fact that there may be hundreds/thousands/millions of people peering into their world. Fewer still...

Sam