I think the reason is that the scope of 43 Things is so enormous -- goals can be anything, in any domain. It's great to learn a little bit about a lot of interesting things, but when I'm really trying to learn something about a specific topic, I'll go to a more specific source. One of the best uses of 43 Things seemed to be in helping people figure out potential travel destinations, which had a more focused feel. So the creators have built a flavour called 43 Places to focus on that task. It's pretty cool -- I want to go to PEI. I love this kind of learning, and it's very cool how they've integrated Flickr feeds based on tags. It's a richer experience than the text-heavy pages in 43Things. (Thanks to Will)
I've also been saving Scott's post about plans and portfolios, extending a short discussion we had earlier this year on 43Things. I like his distinction between plans and goals, and I think this is going to be an important part of how individuals guide their personal learning:
"Sometimes people get the two concepts - plan and goal - and treat them as if they were the same thing. However, a goal is a state you want to achieve; a plan is a strategy for achieving it."