A couple of weeks back, 37signals launched 43things. This is a free collaborative, blog-style to-do list. Basically you put together a list of things you want to achieve and blog about them. Other people can join in doing the same things and comment on your blog. It appears to reuse a couple of chunks from 37signals’ Basecamp application.

Now 37signals have launched Ta-da List. This is a web application that allows you to keep lists of things to do. You can also share publicly or privately (with selected individuals). Another free application developed specifically to encourage people to start using Basecamp.

There is a slight marketing problem though: There is already a personal (free) version of Basecamp that does much more than Ta-da List.