I haven't blogged about weight loss in some time, and for those who liked that series, I apologize.  MSNBC has an interesting, and very confusing article, discussing the pro's and con's of weighing yourself daily.  They come out on the size favoring daily weigh ins (which is a theory I do not subscribe to):

Several well-controlled studies found that daily weighing helps with both weight loss and the prevention of weight gain. A study from the University of Minnesota looked at the influence of the frequency of self-weighing on weight change in more than 3,000 adults enrolled in either a weight-loss trial or a weight-gain prevention trial. Higher frequency of weighing was found to be associated with greater weight loss or less weight gain over the two years of the trials.
...
Participants who weighed themselves daily and who learned to take quick action when their weight started to creep up did significantly better at maintaining their weight loss than a control group that received a quarterly newsletter about eating and exercise.

First of all, I think that is a bad comparative survey.  The more interesting survey would have been to add a third group (besides the control) which weighed themselves weekly, which is what I personally recommend.  Why weekly instead of daily you ask?  Well, at the very end of the article on MSNBC, they give some important information which I think contradicts the daily weigh-in advice, but they fail to draw the correct conclusions about it:

Don't even think about weighing yourself more than once a day — the numbers will simply reflect what you just ate and your fluid balance.
...
If you are trying to lose weight, look for a general downward trend of 1 to 2 pounds per week with some fluctuations. Remember that fluctuations of several pounds from day to day are normal.

Think about that.  Over a week you can expect to lose 1 to 2 pounds as part of a trend.  But during that week, your weight can fluctuate daily by several pounds up or down!  So comparing today's weight to yesterday's weight can be pretty meaningless, especially for women who's weight can fluctuate vastly due to normal body cycles more than men.

But then why does the study seem to justify daily weigh-ins?  The only reason I can think of is that it keeps you in a weight loss mindset.  Your daily weights are still meaningless, but it keeps you thinking about your weight constantly.  I'm sure this helps with weight loss, but I'd like to see comparative numbers to a weekly weigh-in schedule.  Daily weigh-ins used in this way could lead to unhealthy expectations for weight loss, and unhealthy eating habits.