I really like the idea behind beeminder, as it focuses on discipline/process more than the outcome, but it looks like I could accomplish this with a spreadsheet, reminders, and a 'swear jar' of cash I actually get to keep.
Might work for some people.
(It's possible that the tracking alone will be motivating. Some people, for some goals, find that to be the case.)
I'd love to hear how it goes for anyone who sets up a DIY Beeminder!
You're very right it would depend much on the person AND the goal.
The main value I personally see here is the setup. I wouldn't have to set up reminders and tracking manually. I may even learn a new goal I hadn't considered if others share their goals. As long as it doesn't devolve into a perfectionism race to the burnout line.
I hope it results into more a tool for self improvement than yet another business preying on human flaws/needs.