Back in Seattle, SaturdayHouse originally had a contribution-based model. It seemed that people who paid also felt that they should participate because they had paid for the month.

Were this effect super-powerful, everyone would be fitness freaks, exercising every day because they had paid for their membership to the gym. Is this effect illusory or does it actually have some weight?

With planhack, people login, use it for a bit, then disappear for a month or two, then start using it again, and then fall off the wagon. So we apparently need a nudge to keep planning. I could send nag messages, however I know how I react to being nagged. ;)

I think you should totally spruce up planhack, add recurring donation buttons, and email it to lifehacker. I've definitely been one of the few people who kept coming back to it (until finally realizing that maybe, for myself, I wanted something bespoke. And being a hacker means that I can make said tools.) But I think it's the kind of tool that a non-trivial percentage of the population would find useful, if they knew about it. Donating would probably help, too. The gym thing is interesting. From my own experience, I found that lowering the transaction costs for each visit helped immensely. In Seattle, my employer paid for the gym, if I opted out, I could have gotten a minimal kickback (maybe $15 or $20 each month). So I chose an apartment that was less than 2 minutes by car - yes, 120 seconds or less - or 5 minutes on foot, and ended up going nearly every day. In San Francisco, on the other hand, I paid $100 each month but it was minimally further (2-3 traffic lights away) but the activation energy to go felt very high. Saturday House on the other hand was 15 miles away from my place, but because it was a much greater investment (several hours) less frequently (once a week) it felt like it warranted much more dedication. Plus, who're we kidding, it was damn fun. Productivity tools on the other hand, it feels like the cost serves to remind of an investment, if minimally so. That's why I like the Remember the Milk (RTM) model, some nominal ($20?) fee per annum. Every time I've been tempted to try a new Todo system, I'm reminded that I've paid that fee. Or the license fees for OmniFocus or the like. Doesn't always stop me from moving on, but it's always a reminder. --rkabir