I think the question refers to an experiment begun in 2009, initiated by Cambridge professor Tim Gowers, and still active (https://polymathprojects.org) in research mathematics. This initiative is called polymath projects, which is a wordplay on the word polymath. The idea is to make a “massive” collaborative effort with anyone in the world being invited to contribute bringing in different knowledge and competences. A project consists of a  selection of an unsolved problem, sufficiently interesting but expected not to be too hard, and that some people think would be suitable for a collaborative effort. It takes the form of a blog from what I understand.

These efforts have had some successes and perhaps some set-backs and has received scepticism from some other leading mathematicians. One trouble that I think arise is that sometimes the main progress is made by a single person providing the crucial idea which leads to a quantum leap in progress. (Progress is not always continuous, maybe rarely so? comments?) It will then be less natural to incorporate it into the collaboration, also the individual person may want more credit for herself (this can be a matter of getting a good job, or an award giving money — so it is not a superficial concern).

Some polymath projects have been successful, this is not surprising since it involved a large effort, so it does not necessarily mean that polymath projects is a good approach. One should, like an economist, when evaluating its benefits, ask about the alternatives? Maybe other approaches are more efficient, maybe it depends on the problem, can one identify suitable problems in advance?

Are there other examples of such collaborations in other domains?