In our weelky meetings we write down each task that needs to be done and the name of the person in charge, then send it by email. Even if there is no follow-up the next week, we observed that stopping to send the emails leads to less work done (or, at least, not the work that is expected to be done by the managers)
Also note that your example is of something very different, as it is not personal goals of the person being put in charge of the tasks, but tasks put in place to carry out a duty to someone else.
With personal goals, publicly committing to them will rarely lead to a strong negative reaction if you fail.
In fact, Robert Cialdini found that commitment was an excellent form of motivation. "If people commit, orally or in writing, to an idea or goal, they are more likely to honor that commitment because of establishing that idea or goal as being congruent with their self image. Even if the original incentive or motivation is removed after they have already agreed, they will continue to honor the agreement. For example, in car sales, suddenly raising the price at the last moment works because the buyer has already decided to buy."[1]
Cialdini performed his original research several decades ago, but it has been continued by the Freakonomics/Kahneman/"Nudge" crew. To the best of my recollection, all of their experiments showed a strong positive effect when public commitment was added. It's the principle behind StickK.com, as well.
Perhaps there are certain types of improvements (vague self improvement was mentioned elsewhere in this thread) that are harmed by external reinforcement, but I think that's more the exception rather than the rule.
[1] http://en.wikipedia.org/wiki/Robert_Cialdini (also check out his "psychology of influence" book for more on the topic)
It's the best motivator for some people for some tasks. People and tasks are infinitely varied.
"In our weekly meetings ..."
It's interesting to ask whether motivation works differently for public-ish work tasks versus private goals.
Results is more explaining to many and less doing :)